UK Caving

TECHNICAL FORUMS => Equipment => Topic started by: Antwan on November 17, 2014, 03:12:25 pm

Title: Merged topic - Spit and BP bolt removal/replacement
Post by: Antwan on November 17, 2014, 03:12:25 pm
Politics aside, When re-equipping a route with resin anchors is drilling out the old spits and re-using the holes a good or bad idea?

The route I question is traverse that is little used next to a CNCC eco anchor rigged pitch.
Title: Re: replacing spits with resin anchors
Post by: Badlad on November 17, 2014, 03:29:40 pm
I would suggest that;

From a conservation point of view this would be a very good idea.

From a practical point of view it is more effort to remove the old spits.

From a safety point of view I expect there are some issues with stressed rock, but I suspect that the deeper and wider hole size of the resin anchor should mitigate any of these problems, especially if the resin anchor only stresses the bottom of the hole.

Then again I'm no expert  :)
Title: Re: replacing spits with resin anchors
Post by: SamT on November 17, 2014, 04:39:18 pm
Pretty much what he said.

Its a bit of a faff trying to remove old spits and they are not too unsightly once they are old. 

I think the zone of stress from them is cone shaped..from the bottom of the spit back towards the surface of the rock if that makes sense. 
Title: Re: replacing spits with resin anchors
Post by: SamT on November 17, 2014, 04:42:07 pm
(http://www.drillcogroup.com/maxi_bolts/engineering/appb_fig5.jpg)
Title: Re: replacing spits with resin anchors
Post by: SamT on November 17, 2014, 04:48:11 pm
Hence if you think about how shallow a spit is.. it gives you a rough guide to how little of the stressed area your resin anchor will pass through.
Title: Re: replacing spits with resin anchors
Post by: andrew on November 17, 2014, 05:09:20 pm
I believe the stress cone disappears when you remove the old anchor, however there may still be damage. Given that, as has been said they are very shallow so it is limited.
Yes it is a real pain to remove an old spit or equivalent, and does take longer, but really on the scale of time for use and coservation of the cave, should we not be trying to replace as much as possible.

Slightly more concerning is if people are not reusing resin anchor holes, which I ave heard rumours (but no evidence)

Also the BP anchor that is part of the current BCA scheme have a spiral that completly fills the hole, so the resin cannot be drilled out. Before I place anymore I would like to  know how these are removed and the hole reused? (Don't answer in this thread, I will start another)
Title: Replacing BP anchors
Post by: andrew on November 17, 2014, 05:10:13 pm
The BP anchor that is part of the current BCA scheme have a spiral that completly fills the hole, so the resin cannot be drilled out. Before I place anymore I would like to  know how these are removed and the hole reused?
Title: Re: replacing spits with resin anchors
Post by: Antwan on November 17, 2014, 05:15:31 pm
Thanks, pretty much what I remember from talking to Chris whatshisface from DMM about the ECO part of the eco anchor partly been about re-using holes ( about 7 years ago now maybe?)

Just wanted to make sure and canvas a few opinions
Title: Re: replacing spits with resin anchors
Post by: Bob Mehew on November 17, 2014, 05:21:59 pm
Andrew beat me to it.

Sorry to say I think it is a little more complicated than Sam's diagrams imply.  There are two states, one when the anchor is not loaded and the other when it is heavily loaded.  Sam's diagrams reflect a theoretical heavy loading condition which I never managed to bottom out.  I believe the 90 degree cone angle is based on a simple argument reflecting the inverse of a soil spoil heap (where the soil has no cohesive strength).  But I have also come across a 60 degree cone angle and not been able to get a handle on why that angle.  (I suspect it reflects the degree of cohesion of the rock or compressive strength.) That is why you get slightly differing arguments that you should not place anchors closer than either 1.5 or 2.0 times the depth of the anchor so as to avoid overlapping the cones.

But the anchor spends most of its time unloaded and thus for a spit (or expansion anchor) the stress on the rock is localised around the bottom of the hole. I don't have comparative strength data of rock and metal to say whether the rock is so stressed as to cause it to suffer deformation of some form or it is just the metal which deforms.  Looking at some expansion anchors, my guess is the metal suffers, not the rock. 

A point first made by Simon Wilson is that post resin failure, the Bolt Product anchor appears to transfer its load much further up the shaft (at the point where the shaft switches from straight to coil) whilst the DMM Eco anchor does near the base (where the tangs are located).  I await Simon's report on reusing holes with his anchors.  I have no recollection of tests being done on old spit holes.

There is also the point that often the best spot for locating the anchor is taken by the spit, so devising a simple means of extracting it would be beneficial not just from a conservation view point. 
Title: Re: replacing spits with resin anchors
Post by: Pete K on November 17, 2014, 05:29:38 pm
On the subject of removal of old Spits - it my be worth speaking to Bob Dearman (DCA Equipment Officer). He recently proposed removing old Spits that were no longer required so I assume he has a method for doing so.
Title: Re: Replacing BP anchors
Post by: Bob Mehew on November 17, 2014, 05:47:14 pm
I am not aware of any work having being done to extract them other than by using an anchor puller.  (I welcome being proved wrong.)  But as a starting point, one has the same problem with all resin anchors with a need to drill through both metal and resin.  In theory one should be able to design a simple anchor puller which could be used in confined spaces.  Simon Wilson's puller is much smaller than the BCA one and has at its heart the mechanism from a screw jack.  But that used a meter long handle to apply the force.  (I recall attempts using a clutch puller were blighted by the lack of a long enough handle.)     

Whilst I can't speak on behalf of BCA's E&T Committee, I for one would look favorably on an application to fund the building of such a puller.
Title: Re: Replacing BP anchors
Post by: andrew on November 17, 2014, 06:10:56 pm
Hmmm, that is what I thought.
DMM anchors: I have removed a few, and you can get a 5mm bit (smallest sds I could find) and drill down the sides, taking out the resin, only just clipping the metal. A bar can then be used to twist the anchor, breaking the rest of the resin. Then the bca test puller can pull them out, although it still requires it to be wound up to max (10KN from memory) then it takes minutes for it to be fully extracted.
With the BP anchor, a metal drill could be used, but the worry would be that it would break up, when the puller is used. I have some resin that is a couple of months out of date, maybe I will try it on an anchor.
Title: Re: Replacing BP anchors
Post by: Bob Mehew on November 17, 2014, 06:50:10 pm
One problem with BP anchors is you will have to initially drill through resin before you get to the metal coil.  And to avoid confusion, the 10kN puller you refer to is manufactured by Hydrajaws see http://www.hydrajaws.co.uk/ (http://www.hydrajaws.co.uk/) where as I was referring to the BCA manufactured puller, see http://www.cncc.org.uk/documents/anchor_test_316_date_23_november_2013.pdf (http://www.cncc.org.uk/documents/anchor_test_316_date_23_november_2013.pdf) which is a totally different beast.  (I took it underground in a wheel barrow.)

I concede we need to do some tests with BP anchors in 18mm and possibly 20mm holes to allow for damage to the rock hole side whilst extracting the anchor.  I also concede one probably does need to do some drilling to weaken the BP anchor to avoid breaking the rock surface which is experienced when just pulling them.  (It is worth noting Simon Wilson has experienced little if no rock damage in extracting anchors as part of his test program.)
Title: Re: Replacing BP anchors
Post by: Mark Wright on November 17, 2014, 07:13:22 pm
You can put a 20kN gauge on a Hydrajaws pull test rig which should make extraction a bit easier.

Mark
Title: Re: replacing spits with resin anchors
Post by: Badlad on November 17, 2014, 07:14:40 pm

Yes it is a real pain to remove an old spit or equivalent, and does take longer, but really on the scale of time for use and conservation of the cave, should we not be trying to replace as much as possible.

Slightly more concerning is if people are not reusing resin anchor holes, which I ave heard rumours (but no evidence)


I was told that 20 -30 Peco anchors which were decommissioned in Rowten Pot Gully have been hammered flat and smeared with resin and mud as the favoured option.  I believe that the route has now been rebolted with the new BP bolt as well, although I have not seen this myself.

More here http://www.cncc.org.uk/documents/PECOAnchorDecommissioning.pdf (http://www.cncc.org.uk/documents/PECOAnchorDecommissioning.pdf)
Title: Re: replacing spits with resin anchors
Post by: Simon Wilson on November 17, 2014, 08:25:03 pm
We have two threads on almost the same topic so I'll stick to this one.

If a Spit has a good thread in it then it is quite easy to pull it out. If the thread is gone then I don't know how to do it and would welcome suggestions. I've been shopping around for a diamond core drill that will drill around a Spit. It might be worth a shot. You would only need to drill about 25mm deep then you could probably get the rest out with a small chisel.

In the early days of the DMM Eco hanger one of the selling points was that at any time in the future they could be removed and the hole reused and that has proved to be true - the clue is in the name. Nobody has come up with a method of a removing a BP anchor.

On my website I say that I intended to test IC anchors installed in previously used 12mm holes. Yesterday we pulled out four such anchors. I haven't had time to write up the results on the website. But I can tell you the anchors pulled out at peak loads better than the first time the holes were used. I expected that result and I will explain why on the website. The lowest of the four pulled out at 34.91kN.

We also pulled out an IC anchor that had been installed in an 18mm hole. This pulled out at 35.14kN. I intend to test a few more in 18mm holes.

I am in the process of making a compact puller that can be used in caves to extract anchors. I want to be able to demonstrate that IC anchors can be extracted without damage to the rock because I think that is an essential requirement of any resin anchor for caving or climbing.
Title: Re: replacing spits with resin anchors
Post by: cavermark on November 17, 2014, 08:54:25 pm

I was told that 20 -30 Peco anchors which were decommissioned in Rowten Pot Gully have been hammered flat and smeared with resin and mud as the favoured option.  I believe that the route has now been rebolted with the new BP bolt as well, although I have not seen this myself.

More here http://www.cncc.org.uk/documents/PECOAnchorDecommissioning.pdf (http://www.cncc.org.uk/documents/PECOAnchorDecommissioning.pdf)

What about drilling through the anchor head with a cobalt drill bit? 

Is a portable grinder (with a suitable mask and rope access techniques) really not an option? Makita do a grinder that fits the same LiIon batteries as their SDS drills now.

The resin splodging seems pretty unsightly, especially for waterwashed sections (and would make future attempts with portable grinders or pulling devices pretty much impossible)....
Title: Re: replacing spits with resin anchors
Post by: Simon Wilson on November 17, 2014, 09:06:37 pm
It would be impossible to drill the anchor enough the get it out.

Pulling out a BP anchor will never be an option because the design of the BP anchor means that the rock breaks when it's pulled out.

Title: Re: replacing spits with resin anchors
Post by: andrew on November 17, 2014, 09:13:07 pm
As others have said, one if the big selling points was that the anchors could be removed, mainly so we did not run out of rock to place in. Yes it takes about an hour, but if we are to conserve this delicate environment, it should be done. (And I have done it myself so I am putting my money where my mouth is)

As for spits although not available a couple of years ago, things like this are available

http://www.amazon.co.uk/Marble-Ceramic-16mm-Diameter-Drill/dp/B0053OFGNE/ref=sr_1_6?ie=UTF8&qid=1416249091&sr=8-6&keywords=16mm+core+bit (http://www.amazon.co.uk/Marble-Ceramic-16mm-Diameter-Drill/dp/B0053OFGNE/ref=sr_1_6?ie=UTF8&qid=1416249091&sr=8-6&keywords=16mm+core+bit)

Hopefully will work, anyone think of any reason why not, I think I will get one.

Spits: if the thread is good and they were a hand spit (12mm) yes a puller with a punch down the centre works. Drill spits are coned the other way, and the thread breaks. Cobalt drills dud very little.
Title: Re: Replacing BP anchors
Post by: Bob Mehew on November 17, 2014, 09:16:03 pm
Typically we are talking about 30+kN to extract Eco & BP anchors.  You need to weaken the placement before pulling.   
Title: Re: replacing spits with resin anchors
Post by: Simon Wilson on November 17, 2014, 09:21:52 pm
Andrew,
Yes, that's the sort of core drill but I think you will need to get one with a 12mm bore. You will need a water bottle to wet it. Please have ago and let us know how you go on.

I'm hoping my puller will pull out a DMM in a few minutes.
Title: Re: replacing spits with resin anchors
Post by: Bob Mehew on November 17, 2014, 09:39:40 pm
I speak without practical experience but my memory is grinding heads off was considered to be dangerous given you almost certainly were hanging from a single rope which is likely to be located in the work area.  Would I be right in suggesting industrial rope access techniques require a number of anchors so as to organise several ropes to the work location in order to get them out of the way of the grinder?  One could use a hacksaw but that would take a fair amount of effort (and probably spare blades).

Extracting the Eco or BP anchor either requires one weakens the resin by drilling into it so as to enable the anchor to be pulled out with a much lower force or else one removes the head and drill in to remove the whole lot.  BP anchors are know to crack the surrounding surface rock on extraction without prior weakening.  I don't think anyone has tried weakening the resin before pulling them.  Eco usually came out cleanly with (or without) prior weakening the resin.

The only challenge I foresee with a core drill is build up of swarf / rock & resin dust. 
Title: Re: replacing spits with resin anchors
Post by: nickwilliams on November 17, 2014, 10:08:31 pm
A battery angle grinder was tried for removal of some of the Peco anchors, IIRC, but the resin quickly gets heated by the metal work and the resulting fumes in the confined space of a cave were found to be intolerable. Mind you, I don't know if this was using ultra thin discs.

Achieving the kind of pull forces required to simply extract an anchor with anything less beefy than the puller used for the test programme will not be easy. The forces involved are significant: for example I tried a straight pull with a 10t hollow hydraulic cylinder and this bent the eye on the puller and easily sheared the M12 8.8 bar I was using as the pull rod (the biggest that would fit through the hollow cylinder). Obviously stronger materials are available but this rapidly becomes a custom made solution requiring considerable effort and expense.
Title: Re: replacing spits with resin anchors
Post by: Simon Wilson on November 17, 2014, 10:10:32 pm
If cutting the heads off resin anchors or bending them over became acceptable we would end up with bolt rash. We should not install any anchor which can't sustainably be removed.

In the case of Spits, diamond core drills will only drill rock. The dust is removed with water.
Title: Re: replacing spits with resin anchors
Post by: Simon Wilson on November 17, 2014, 10:13:57 pm

Achieving the kind of pull forces required to simply extract an anchor with anything less beefy than the puller used for the test programme will not be easy.


I'll let you know how I go on.
Title: Re: replacing spits with resin anchors
Post by: cavermark on November 18, 2014, 12:30:00 am
It would be impossible to drill the anchor enough the get it out.


To clarify - I was suggesting that, in the case of Peco anchors, if the "Bolt"head is drilled off, the hanger would be removed. The shaft of the anchor would still be in the rock, but flush with the surface - the same outcome as grinding or hacksawing the head off.  Not ideal but much less noticeable than the resin splodge solution perhaps?

Bob - Rope access for tasks such as grinding would involve 2 ropes (as standard) with "hard links" such as steel strops, between you and your descender and back up device. You would also carefully position yourself and your ropes before starting the work so that any kick back or follow through would not be a problem. The position of the new P-bolts in the CNCC photos look like they could be useful for positioning too.
Title: Re: replacing spits with resin anchors
Post by: andrew on November 18, 2014, 08:34:08 am
We really should not be discussing this. It is ever cavers moral duty to conserve caves to the best standards, while still enjoying access. Anchors should removed and the placement reused. This should be as an important factor, possibly more important than the strength. After all a 40 year life is very short, we are privileged to be towards the start of caving and have a duty to leave the environment in the best condition possible.
Title: Re: Replacing BP anchors
Post by: Maj on November 18, 2014, 11:32:32 am
Thinking outside the box.
What happens if you heat the anchor up with a blow lamp first. Would this have a detrimental effect on the resin and hence provide the weakening required before pulling.
I'm assuming the thermal conductivity of the anchor would be greater than that of the resin, and so the heat will transmit down the anchor heating the boundary between anchor and resin.
 :-\ :-\
If it might work, I appreciate there are other factors to consider, for example:-
Affect on the surrounding rock.
Is there a risk of fumes from the resin?
Perhaps an aluminium plate to protect the surrounding rock and resin from direct heat, might resolve some potential issues.
 :-\ :-\

Maj.



 
Title: Re: replacing spits with resin anchors
Post by: Maj on November 18, 2014, 11:45:40 am
I didn't spot this second related thread before I posted. So I'll repost it here.

What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the weakening required before pulling?
I'm assuming the thermal conductivity of the anchor would be greater than that of the resin, and so the heat will transmit down the anchor heating the boundary between anchor and resin.
 :-\ :-\
If it might work, I appreciate there are other factors to consider, for example:-
Affect on the surrounding rock.
Is there a risk of fumes from the resin?
Perhaps an aluminium plate to protect the surrounding rock and resin from direct heat, might resolve some potential issues.
 :-\ :-\

Maj.
Title: Re: replacing spits with resin anchors
Post by: Roger W on November 18, 2014, 11:58:56 am
You might expand the bolt enough to loosen it when it cools. 

You might get it hot enough to degrade the resin (but watch out for fumes).

You might get the limestone hot enough to convert it to calcium oxide... (825 degrees or so).

Sounds like a suitable case for "try it and see" - preferably somewhere where there's plenty of ventilation and no danger of setting your rope on fire.
Title: Re: replacing spits with resin anchors
Post by: Bob Mehew on November 18, 2014, 12:15:29 pm
Anchors should removed and the placement reused.

We don't start from a clean sheet situation but have a range of different types of anchors which already foul up placements.  So I suggest we do not need to stop all placements of BP anchors whilst we determine if we an extract a BP anchor without fouling the placement location.  Perhaps we can make a stab at seeing if we can remove some resin from a BP anchor and then pull it using the BCA anchor puller.

I am free on Sunday 23rd Nov and currently have the BCA anchor puller.  If someone wishes to place an anchor in a convenient flatish surface location (concrete will do) I am prepared to drive where ever to pull it (I am in South Wales Saturday 22nd evening).  I don't have a battery drill to hand so someone will have to do the resin removal bit for me. 

The puller is booked for weekends of 29 & 30 Nov and also 6 & 7 Dec for use in South Wales.  I am a bit reluctant to offer to do it within that work as the existing plan is to pull 64 anchors which is challenging enoug!  The puller is then scheduled to go onto North Wales.

If we can get this underway, then people may wish to suspend placement of BP anchors, as few weeks delay is surely neither here nor there? 

Or can someone work on it with another puller?

What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the weakening required before pulling?
Interesting thought.  As Roger says, trying it is probably the only answer.  Given the expected low heat conduction of resin, I don't expect the rock to get warm.  But heating the metal anchor would only damage the metal / resin bond.  For BP anchors the challenge is to extract the anchor without spalling the surface of the rock.  I am not sure if destroying the metal / resin bond will help that as one then has to remove the few centimeters of resin between the surface and the start of the BP anchor twist.  Another point to consider is the possible build up of CO2 if one is doing several anchors.  Being techi, I would want to place a thermocouple at the base of the anchor but that need not be done for the first suck and see.
Title: Re: replacing spits with resin anchors
Post by: andrew on November 18, 2014, 12:52:10 pm
If you are in Wales, Mendip is not that far, and it is jrat evening on Saturday. I have al, the kit, just need to find a flat piece of rock, big enough, but we should be able to do that.
Title: Re: replacing spits with resin anchors
Post by: SamT on November 18, 2014, 01:30:33 pm
What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the

http://www.bolt-products.com/SustainableBolting.htm (http://www.bolt-products.com/SustainableBolting.htm)

see the section on "melting out"

I think fumes would be a real problem.

I did wonder if you could warm the metal up using electricity -   Some sort of welder type setup.  I was thinking surface though. Not underground  :o

Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 18, 2014, 01:49:39 pm

Can I just say that before anyone gets too hung up (sic) on the subject of the removal, that if placed well in good rock, the BP bolts should NEVER need replacing (well - in theory)

The old DMMs on garlands in giants are probably the most frequently used bolts in the country and after ~20 years, are showing no signs of wear.

The only time we've had to drill out and replace bolts are where numbskulls have been lowering cavers down pitches directly off bolts causing them to wear thin.

I grant you the fact that having a bolt that is relatively easy to remove and replace is preferable.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 18, 2014, 06:38:31 pm
I grant you the fact that having a bolt that is relatively easy to remove and replace is preferable.

I agree wholeheartedly Sam.  :thumbsup: That's why I've been using Excalibur Screwbolts for years in the Manifold. There are a couple in Darfar Pot that are under water for much of the  year which I need to replace next year because of corrosion, but I can just unscrew them and screw new ones in using the same hole.

See:- http://www.excaliburscrewbolts.com/ (http://www.excaliburscrewbolts.com/)

Also, Excalibur are producing new Screwbolts now with corrosion protection that is apparently comparable to stainless steel... Will be trying them next year for the replacements I think.

Not covered by the BCA insurance scheme of course, but got fed up of waiting for DCA installers to install p-bolts. They get light usage too, of course...

I should also add that those eyebolts which will need replacing have been in there for 8 years and are still sort of OK, but I want to make sure they are safe. not that many people go down there. I may replace them with m12s as well instead of the current m10s, again just cos they'll last longer. The one above river level have hardly corroded at all and are all fine...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 18, 2014, 06:57:31 pm

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 18, 2014, 07:12:41 pm

I agree wholeheartedly Sam.  :thumbsup: That's why I've been using Excalibur Screwbolts for years in the Manifold. There are a couple in Darfar Pot that are under water for much of the  year which I need to replace next year because of corrosion, but I can just unscrew them and screw new ones in using the same hole.

See:- http://www.excaliburscrewbolts.com/ (http://www.excaliburscrewbolts.com/)

Also, Excalibur are producing new Screwbolts now with corrosion protection that is apparently comparable to stainless steel... Will be trying them next year for the replacements I think.


Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Pete K on November 18, 2014, 07:26:21 pm

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

I suspect that the various regional councils can only operate as fast as the volunteers who install the bolts do. Most of whom have jobs and lives to fit dragging drills and batteries into the deepest parts of the uk around. I don't think it is a failing of the BCA, more volunteers are required surely?
The volunteers who bolt for the DCA seem to get thinks done quickly.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Grizzlybear on November 18, 2014, 07:32:07 pm
Maybe before erasing all traces of previous exploration methods, including the repair of rock grooved by lifeline and wire tether. We could  reflect on Gibbons his account of Rome should be enough for most people ,however we still enjoy finding and preserving  Roman artifacts. To move on. I am sure most modern anchorage placers will consider the placement position of old spits ect. would be totally unsuitable for modern rope techniques These may often have been placed in a position for short term gratification rather than any long term considerations
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 18, 2014, 07:32:31 pm

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

True, but in my case the current anchors can be removed in minutes, the existing hole reamed out to the required size and a resin bolt installed in it's place. They have been placed in sound rock in good positions. Under the river bed level however it would be interesting to see how quickly they corrode as they would be submerged in acidic water for many months of the year. Down there I'd rather have anchors I could replace easily in minutes rather than having to go through all the faff that has been discussed in this thread. (Drilling out bolts and resin, etc.) Different situation to most caves in the country. about 25ft. below highest flood level.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 18, 2014, 07:39:30 pm
Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...

These aren't popular caves Mark, that's the point. And of course they could still be glued in place, but that sort of spoils the whole idea. These anchors will need replacing much more often cos they are under water for much of the year.

I'm quite happy for the above river level ones to be replaced with resin anchors and indeed have been asking for this to be done for several years, but everybody has been too busy doing caves further North as usual...  :coffee:
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: paul on November 18, 2014, 08:15:00 pm
Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...

These aren't popular caves Mark, that's the point. And of course they could still be glued in place, but that sort of spoils the whole idea. These anchors will need replacing much more often cos they are under water for much of the year.

I'm quite happy for the above river level ones to be replaced with resin anchors and indeed have been asking for this to be done for several years, but everybody has been too busy doing caves further North as usual...  :coffee:

Possibly because "These aren't popular caves " and therefore sit sowewhat lower down in the list of caves to be done?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 18, 2014, 08:49:53 pm
Sorry, I meant the Excalibur type bolts could be considered instead of resin bolts for any given cave; but that they would be likely get pinched if said cave was popular...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: pwhole on November 18, 2014, 08:55:16 pm
I've just bought a box of Excalibur bolts for a site specifically because they'll need to be removed again later, some (hopefully) to be resin-bolted properly at a later date - I'm quite pleased this option is available as it means we can use the 'best' spots to rig from without ruining them, rather than rigging around the best spots and making things much more difficult for ourselves. That said, even empty holes isn't ideal, so will still aim to use as few as possible, as it is 'kind of' virgin territory. Haven't used any yet, but I'm looking forward to trying them out. Wasn't sure how long they'd last in a wet environment, but it sounds like you're having no problems so far Mel.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 18, 2014, 08:57:54 pm
These may often have been placed in a position for short term gratification rather than any long term considerations

Now we have the internet I guess that won't go on so much?   ;)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 18, 2014, 09:04:04 pm
pwhole - they've been used quite a lot in rope access now - I've been surprised that they have passed pull tests at 7KN, even in soft looking sandstone or brickwork.
If placed well I guess they should be good until the bolts corrode. Obviously, if frequently removed and replaced the thread in the holes will wear and reduce holding power.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 18, 2014, 10:42:06 pm
Im a big fan of the exalibers. I've used them in baggers for short term stuff.  That's turned into long term as I've not been back yet to replace them. But it will be nice to be able to just unscrew them and ream out the hole for a resin.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 19, 2014, 03:39:56 am
yeah, hole wear would be an issue but the ones in the Manifold have never been replaced. I use M8s for deviations then M10s for main belays, usually in pairs obviously. If they were being screwed and unscrewed a lot and hole became worn just upgrade to the next size up, ie:- M12s. Beyond that then yes, you'd to replace them with resin bolts... or expanding anchors like Rawlbolts, but obv. they stress the rock so have to be placed carefully...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 19, 2014, 04:13:06 pm

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

I suspect that the various regional councils can only operate as fast as the volunteers who install the bolts do. Most of whom have jobs and lives to fit dragging drills and batteries into the deepest parts of the uk around. I don't think it is a failing of the BCA, more volunteers are required surely?
The volunteers who bolt for the DCA seem to get thinks done quickly.

I don't think you appreciate what I said. There are a number of difficult potholes that are infrequently visited, that are the places where we would least want to have an accident and which have never had resin anchors installed under the BCA scheme. In these holes people would have to rely on 20, 30 or 40 year-old Spits or provide their own alternative. There have been people willing to install resin anchors but they have had no anchors available under the BCA scheme.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 19, 2014, 04:39:56 pm
Simon - Would excalibur type bolts be a good interim measure for some of the sites you are referring to?  The holes can then be reused for whatever resin anchor gets decided upon and becomes available....

It does seem like things are moving forward now...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 19, 2014, 05:54:16 pm
Mark.. there are plenty of BP bolts available. BP bolts have 'been decided upon' already.  There only real issue with them that anyone can come up with is that they might be quite tricky to remove (oh the irony).  Given my comments with regards the garlands bolts.. I cant see a well placed bolt BP bolt in quaking pot is going to need replacement ........ ever.
The same goes for the bolts in mels caves. 

I am failing to see that there is a big issue here.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Antwan on November 19, 2014, 06:10:29 pm
Agree with you Sam, place the right stuff first time then 20 years later there's a decent anchor and not a rusty spit.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 19, 2014, 07:28:22 pm
Yes put the Right bolt in first time. Not convinced by bp, it is meant to go in a 16mm hole, but I and other installers have found, even with a brand new bit, it really does not fit in without a hammer, then difficult to get out, so testing hole is not easy. Would not be good in Quaking.

As for wear, the anchor on Swildons 20 was replaced as it loose, many years ago. Showed signs of wear, not from rope, but mailion used for the ladder - proving Swildons is the centre of the universe not Garlands pot  ;D
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 19, 2014, 09:52:22 pm
Mark.. there are plenty of BP bolts available. BP bolts have 'been decided upon' already.  There only real issue with them that anyone can come up with is that they might be quite tricky to remove (oh the irony).  Given my comments with regards the garlands bolts.. I cant see a well placed bolt BP bolt in quaking pot is going to need replacement ........ ever.
The same goes for the bolts in mels caves. 

I am failing to see that there is a big issue here.

SamT,
You are content that BP bolts have been decided upon. Technology advances all the time and there is now another anchor on the scene. It's just things moving on as they will and no big issue.

Over the past few years many of the more difficult potholes in the Dales have been fitted with an assortment of stainless through bolts and various types of resin anchors. If the big pitch in Quaking hasn't been done and a team of fit young tigers take on the challenge and if they choose to use IC resin anchors, they will be using anchors that drop smoothly into 12mm holes and they will be able to install three of them using a lightweight drill and one 14.4 volt battery.

http://www.resinanchor.co.uk/ (http://www.resinanchor.co.uk/)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 19, 2014, 10:53:39 pm

Not convinced by bp, it is meant to go in a 16mm hole, but I and other installers have found, even with a brand new bit, it really does not fit in without a hammer, then difficult to get out, so testing hole is not easy. Would not be good in Quaking.

Thats why I start the hole with an 18mm bit for the first 3/4 inch or so, then switch to a 16mm bit. Negates all issues with getting the bolt stuck.

Quote
As for wear, the anchor on Swildons 20 was replaced as it loose, many years ago. Showed signs of wear, not from rope, but mailion used for the ladder - proving Swildons is the centre of the universe not Garlands pot  ;D

What was it replaced with out of interest.

You are content that BP bolts have been decided upon.

I am, and the point I was making is that they are freely available for installation.  It seems to be that foks have the notion that there are still no bolts available, which is certainly not the case. 

Quote
Technology advances all the time and there is now another anchor on the scene. It's just things moving on as they will and no big issue.

Totally agree, I don't have a problem with product development.

Quote
they will be using anchors that drop smoothly into 12mm holes and they will be able to install three of them using a lightweight drill and one 14.4 volt battery."

Good stuff.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 20, 2014, 08:05:28 am


That's why I start the hole with an 18mm bit for the first 3/4 inch or so, then switch to a 16mm bit. Negates all issues with getting the bolt stuck.

Technically, that has not been tested, I asked if BP could use 18mm holes, and was informed, that as it had not been tested, they could not. (This was a year ago, so might have changed now)

What was it replaced with out of interest.

Anther DMM. As this was the original spit hole, it is the third anchor in the same spot.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 20, 2014, 11:25:34 am

Technically, that has not been tested, I asked if BP could use 18mm holes, and was informed, that as it had not been tested, they could not. (This was a year ago, so might have changed now)


Surely if the individual placements pass a test with a pull rig that is good enough?  - they are then highly unlikely to fail, they will be backed up anyway, if they work loose they can be rectified, we are unlikely to return to the manufacturer about it?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 20, 2014, 12:41:34 pm
Andrew - just confirm - I only use the 18mm bit for the first 15mm or so - effectively the same as reaming out the neck of the hole to allow for the widening of the P bolt as it goes from twists to straight just before the eye.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 20, 2014, 04:25:10 pm

Technically, that has not been tested, I asked if BP could use 18mm holes, and was informed, that as it had not been tested, they could not. (This was a year ago, so might have changed now)


Surely if the individual placements pass a test with a pull rig that is good enough?  - they are then highly unlikely to fail, they will be backed up anyway, if they work loose they can be rectified, we are unlikely to return to the manufacturer about it?

I am not aware of results from a test program which would support the use of an 18mm hole for BP anchors.  I am NOT saying you can't use an 18mm hole, indeed there is some information around suggest that you will be able to.  But we need evidence to justify moving away from the anchor manufacturer's recommended installation procedure of using a 16mm hole. 

The problem is the observation that BP anchors frequently showed the rock surface around the hole spalling during the extensive testing program undertaken by CNCC Tech Group.  That may well be sufficient to mean the location can't be reused.  Andrew and I will be doing some tests this weekend to see if this spalling can be minimised.

Also I was informed this morning that around one hundred BP anchors are in BCA's hands available for issue.  (I think that also implies that over three hundred BP anchors are out there either placed or waiting to be placed in cave.)  No one raised a need for more BP 316 anchors at the last E&T meeting on 2nd November.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 20, 2014, 05:16:49 pm
Also I was informed this morning that around one hundred BP anchors are in BCA's hands available for issue. 
Sorry that should be 50ish.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 20, 2014, 05:34:49 pm
AAARARRRRRRRGGGGGHHHHHHH   :wall:

I'm not suggesting using an 18mm hole for the BP bolts.  Nobody needs to test BP bolts in an 18mm hole.

This is just about purely widening the entrance to the hole slightly to allow for the fact that the BP bolts widen just before the eye.  This makes them far easier to place as they don't get stuck when your testing for fit, before applying any resin. An issue that is putting Andrew off placing any more.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: damian on November 20, 2014, 07:06:14 pm
I'm not suggesting using an 18mm hole for the BP bolts.  Nobody needs to test BP bolts in an 18mm hole.

This is just about purely widening the entrance to the hole slightly to allow for the fact that the BP bolts widen just before the eye.  This makes them far easier to place as they don't get stuck when your testing for fit, before applying any resin. An issue that is putting Andrew off placing any more.
The problem with doing this is that each Region has an approved procedure which, for most regions is extremely prescriptive and to install anything in a method which is contrary to this would make it rather difficult for BCA / the Region in court if the need every arose.

Personally I am very unhappy at the amount of hammering of a BP anchor I have to do to get it into a 16mm hole. I am no engineer but it cannot be good for the anchor!
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 20, 2014, 07:24:48 pm
AAARARRRRRRRGGGGGHHHHHHH   :wall:

I'm not suggesting using an 18mm hole for the BP bolts.  Nobody needs to test BP bolts in an 18mm hole.

This is just about purely widening the entrance to the hole slightly to allow for the fact that the BP bolts widen just before the eye.  This makes them far easier to place as they don't get stuck when your testing for fit, before applying any resin. An issue that is putting Andrew off placing any more.

SamT,
You have made it clear what you are describing. But any anchor needs to be tested in 18mm holes if it is going to be used to replace DMM anchors in the same hole. For those who might not know, DMM anchors fit in an 18mm hole and BP anchors are supposed to fit in a 16mm hole.

It seems to me that if installers are having problems installing BP anchors in 16mm holes, making their own ad hoc solutions and not adhering to a uniform procedure then there is a failure in the system. Is there a specified procedure for installing the BP anchor? If there isn't then there should be and it should be the same procedure that has been established to work properly during testing.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 20, 2014, 09:05:04 pm
I've never installed one of the new bolts but I do have one of the twisted types on my windowsill at work. I got it from Bob Dearman a good few years ago. I assume they are similar.

If you can't get the bolt into a 16mm hole without belting it with a hammer then I'm with Damian. That can't be right. I can't imagine they were designed to have an interference fit. 

There could be inconsistencies in the manufacture of the bolt, assuming you didn't have to hammer the original test bolts into a 16mm hole.

The holes might not be being drilled consistently.

To be honest I don't think many people would be able to drill a 16mm hole with a heavy cordless drill, possibly in one hand, at arms length whilst dangling in a harness. Its a long hole to be able to accurately drill with your feet on the ground.

Simons 12mm hole is very appealing……… Ooo errr

Mark



Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 20, 2014, 09:15:36 pm
The problem with doing this is that each Region has an approved procedure which, for most regions is extremely prescriptive and to install anything in a method which is contrary to this would make it rather difficult for BCA / the Region in court if the need every arose.


Is there really much likelihood of ever ending up in court over bolts in caves?
Especially if tested with a pull rig after installation (I know that's a major ball ache in some caves but it's only the same size/weight as an sds drill)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: bograt on November 20, 2014, 09:16:53 pm
Then again, there's always the issue of wear on the drill bit??
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 20, 2014, 09:36:29 pm
I assumed they would check that before they went underground as part of the installation procedure???

Mark




Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 20, 2014, 09:46:35 pm
Is there really much likelihood of ever ending up in court over bolts in caves?
Especially if tested with a pull rig after installation (I know that's a major ball ache in some caves but it's only the same size/weight as an sds drill)
The testing you reference was stopped by BCA so technically it is being done against BCA's position.  (It is very easy to break the surface resin as the anchor head will flex unless the test load is applied in a particular way which is not a simple axial pull.)  I think only DCA do test.

To be honest I don't think many people would be able to drill a 16mm hole with a heavy cordless drill, possibly in one hand, at arms length whilst dangling in a harness. Its a long hole to be able to accurately drill with your feet on the ground.
One feature of this system is that the hole must NOT be smooth.  The irregularities in the hole make for a mechanical interlock between resin and rock so that if the bond should fail (and they have in a few cases), the block of resin and anchor can still resit a reasonable pull.

AAARARRRRRRRGGGGGHHHHHHH   :wall:
Sorry SamT I should have indicated that I was suggesting doing the 18mm hole work so BCA did not have a panic on its hands when the first demand to replace an Eco with a BP came in.  (Hopefully not in the next few weeks.)

Andrew's concern is not size of hole, it the simple and rather uncomfortable fact that testing BP anchors show many spall the hole edge making it doubtful if one can reuse the hole location.  Eco anchor came out without doing that.  That was something I for one had not given much thought too.  :-[  If we can't show most BP anchors can be got out without destroying the hole location, then perhaps we should revisit whether we should be using BP anchors on conservation grounds.  OK it may not be my life time when they wear out, but conservation is not just about the next 40 years or so.

Then again, there's always the issue of wear on the drill bit??
The number of reports of difficulty getting the anchor into holes suggest it is not drill bit but variation in anchors.  We have not thought (so far) it necessary to measure the anchor 'twist' diameter.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 20, 2014, 10:05:54 pm
From my experience. . And I've installed dozens now both in caves and on climbing routes is that its only the last inch or so, near the eye that gets stuck.  and I agree with Andrew that its a grand royal pain in the ass when you insert the bolt to check the  depth/fit etc and it gets stuck.  Then also then requiring a good tap (nothing more than that in my experience) to set it in the resin. Using the 18mm bit to widen the entrance to the hole has negated all these issues. 

Anyhow.. lifes just too short to carry on going round in little circles on here.  I'll quite happily carry on installing the BCA supplied BP bolts for you all to enjoy until they run out and something else comes along. 

Huge Props to those who have expended huge amounts of time and effort getting us to where we are now and those pushing the progress and development for the future for the wider community.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 20, 2014, 10:17:18 pm

Is there really much likelihood of ever ending up in court over bolts in caves?


Anyone who would make, test or install an anchor thinking that there is not "much likelihood of ever ending up in court over bolts in caves" would not be a suitable person to have anything to do with 'bolts' or anchors.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Hammy on November 20, 2014, 11:38:29 pm
But what about titanium bolts?

These only need a 14mm hole - 'minimum expected life of 50 years and are expected to last for generations'

http://www.titanclimbing.com/Titan%20Climbing%20products%20-%20Eterna%20Titanium%20glue%20in%20bolt.html (http://www.titanclimbing.com/Titan%20Climbing%20products%20-%20Eterna%20Titanium%20glue%20in%20bolt.html)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 21, 2014, 01:13:45 am

Is there really much likelihood of ever ending up in court over bolts in caves?


Anyone who would make, test or install an anchor thinking that there is not "much likelihood of ever ending up in court over bolts in caves" would not be a suitable person to have anything to do with 'bolts' or anchors.

I was implying that the rigorous thinking, discussion and testing of sutiable eco type hangers that has gone on, and the careful procedures and installation that the regional bodies carry out with them, is unlikely to lead to a failure. If there is a failure it is likely to be part of a rigging system that is backed up so will not be catastrophic.
I would have thought the variables involved in installation are more likely to be the cause of any failures and so taking the manufacturer to court is unlikely (but I am only an interested outsider speculating... )

Has there been a court case then involving bolts (excuse my ignorance)?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Antwan on November 21, 2014, 07:30:31 am
Titanium is only a quarter as hard as steel, so I have a slight doubts about actual wear and tear over 50years, especially as a sports climb lower off.

You could always buy one and run  ropes through it every time they get washed?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Hammy on November 21, 2014, 07:54:56 am
Titanium is only a quarter as hard as steel, so I have a slight doubts about actual wear and tear over 50years, especially as a sports climb lower off.

You could always buy one and run  ropes through it every time they get washed?

http://www.titanclimbing.com/Titan%20climbing%20products%20-%20forged%20titanium%20anchor%20rings.html (http://www.titanclimbing.com/Titan%20climbing%20products%20-%20forged%20titanium%20anchor%20rings.html)

http://www.titanclimbing.com/ram's-horns.html (http://www.titanclimbing.com/ram's-horns.html)

Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 21, 2014, 12:32:07 pm

Is there really much likelihood of ever ending up in court over bolts in caves?


Anyone who would make, test or install an anchor thinking that there is not "much likelihood of ever ending up in court over bolts in caves" would not be a suitable person to have anything to do with 'bolts' or anchors.

I was implying that the rigorous thinking, discussion and testing of sutiable eco type hangers that has gone on, and the careful procedures and installation that the regional bodies carry out with them, is unlikely to lead to a failure. If there is a failure it is likely to be part of a rigging system that is backed up so will not be catastrophic.
I would have thought the variables involved in installation are more likely to be the cause of any failures and so taking the manufacturer to court is unlikely (but I am only an interested outsider speculating... )

Has there been a court case then involving bolts (excuse my ignorance)?

You contradicted yourself there. The second part I underlined is correct but the first part appears to be under question.

The installation procedure for BP anchors should have been proved during testing, it should be specified in the installation manual and the latest version of the manual should have been given to all installers. I expect that will have been done so why are two installers having problems and disagreeing in this thread about how to install them?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 21, 2014, 12:49:31 pm
Bob suggested;

'One feature of this system is that the hole must NOT be smooth.  The irregularities in the hole make for a mechanical interlock between resin and rock so that if the bond should fail (and they have in a few cases), the block of resin and anchor can still resit a reasonable pull.'

How are installers taught to drill an 'irregular' hole?

If I were assessing a candidate on an industrial bolt installation course and they drilled an 'irregular' hole they are likely to fail their exam.

Mark
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 21, 2014, 01:01:37 pm
Bob suggested;

'One feature of this system is that the hole must NOT be smooth.  The irregularities in the hole make for a mechanical interlock between resin and rock so that if the bond should fail (and they have in a few cases), the block of resin and anchor can still resit a reasonable pull.'

How are installers taught to drill an 'irregular' hole?

If I were assessing a candidate on an industrial bolt installation course and they drilled an 'irregular' hole they are likely to fail their exam.

Mark

I think you're being a little unfair on Bob. He didn't say that installers should or are taught to drill irregular holes. He said, "One feature of this system is that the hole must NOT be smooth". That is correct and one thing that is specified is that diamond drills should not be used because they produce a smoother hole. I can't remember exactly where that is said but I could find it if I had to.

I have plans to make tool for producing undercuts in holes but it is down my things-to-do list.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 21, 2014, 01:46:08 pm
Simon,

I wasn't having a go at anyone.

Its just the concept of an irregular hole that I was questioning. I understand the idea of having a 'rough surfaced' hole but I was just interested in what installers are actually taught during the course to achieve this. I assume from your comments that one way this is achieved is by not using a diamond drill. What is/are the other way/s of achieving an irregular hole?

I'm just interested thats all.

Mark
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 21, 2014, 03:53:56 pm
I think I have confused myself here too!

Suffice to say I have the greatest respect for the people putting a lot of time and effort into discussing, researching and installing the anchors for the rest of the caving community  :bow:
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 21, 2014, 05:49:30 pm

Installers are "taught" to just drill a hole with a 16mm sds drill bit, just like anyone else might.

The result will be irregular,  maybe not to the a naked eye, but its is thought that the diameter of the hole will vary by small amounts along its length and be rough.  This provides enough of a 'key' that the resin can really stick to it and I believe that its the variances in diameter that mean even when the rock resin interface has failed and the bolt is 'loose' (as has happened on occasion due to holes not being cleaned of dust well enough) they still require huge forces to extract.

It seems to me that if installers are having problems installing BP anchors in 16mm holes, making their own ad hoc solutions and not adhering to a uniform procedure then there is a failure in the system. Is there a specified procedure for installing the BP anchor? If there isn't then there should be and it should be the same procedure that has been established to work properly during testing.

You over exaggerate when you say 'having problems installing'.

As a foot note to my comments re using an 18mm bit at the start. It occurred to me that I've not used that technique on a bolt underground yet.  I started doing this summer on climbing routes.  I've yet to place an underground bolt yet this winter.
I shall refrain using the 18mm trick until the testing has been done!

Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 21, 2014, 06:56:10 pm
Thanks for clarifying that Sam and thanks for putting the effort in. I couldn't do it as the flack would wind me up too much.

I was envisaging wiggling the drill around as the hole was drilled, making it oval shaped. I bet its hard not to get a bit of a wobble going in some of the more awkward locations with such a big and heavy drill though.

I have similar concerns to Bob regarding damaging the rock surface when they are eventually removed. Technically, the ones that are already in should be in the best location available, if they have to be replaced in a different location that is not ideal from a conservation point of view and not ideal for the future generations of cavers.

I'd rather not get drawn into the politics but, a bolt that can be installed with a lightweight drilling machine with a 12mm bit and drills considerably more than 3 holes per battery and doesn't damage the rock when it is removed sound perfect. 

Mark
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 21, 2014, 11:11:14 pm
Like Mark, I wish to avoid dropping into the politics of anchor installation.  But I will comment that:

a) Installation procedures are specified by regional caving councils rather than the BCA E&T Committee.
b) Some resin anchor suppliers do say to not use diamond drills with their product.
c) A reasonably irregular hole will allow for the resin to form a mechanical interlock with the rock if the resin / rock bond should break. 
d) The extent of irregularity has not been defined in numerical terms.  But the irregularities need to be not only across the diameter of the hole but also down the depth of the hole to stop both rotation and / or extraction.   
e) I think there has been a handful or two of anchors placed under the NCA / BCA scheme which have failed at the resin / rock bond out of some 5000 placed anchors.  The irregular hole shape / mechanical interlock has meant that the anchor has resisted extraction under normal forces seen in caving.  (Indeed the reported efforts to remove such anchors suggest the force is a substantial fraction of the peak force for a 'perfect' anchor.)
f) This is one of the 'back up' features of this resin anchor system which give it such reliability.
g) There are many reports that the BP twisted anchor does not easily fit within the suppliers specified 16mm hole.  Indeed one region recommends that installers carry with them a especially 'shaved down' BP anchor (where the twisted part of the anchor has been ground down to remove a fraction of a mm of metal) to use when checking depth of hole and orientation of the anchor head. 

I am grateful to those installers who have freely spoken to me of their experiences within the anchor placement program which enables me to make the above comments.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 23, 2014, 10:05:51 pm
The IC resin anchor website has been updated with the reports of tests on anchors placed in previously used 12mm holes and on anchors placed in 18mm holes and previously used 18mm holes.

Obviously a hole can only be reused if the previous anchor can be removed without too much damage to the rock.

http://www.resinanchor.co.uk/3.html (http://www.resinanchor.co.uk/3.html)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 25, 2014, 09:57:34 am
Andrew Atkinson and myself carried out 4 extractions of Bolt Product anchors on Sunday.  The anchors were place in two boulders, with the aim of one anchor being roughly at right angles to the bedding plane and the other anchor parallel to the bedding plane.  All anchors were extracted using the BCA anchor puller with over 40kN force in the axial mode.  For one boulder, we drilled out a fairly small amount of resin around the heads prior to extracting the anchors.  They both came out with only one small trivial amount of spalling.  In contrast, the other bolder showed massive spalling, covering roughly 50cm by 40cm and 30cm by 30cm of the surface around the hole.  (We had decided to not drill out surplus resin for these two anchors, but consider that this made no difference to the extensive spalling witnessed.) 

The results leave us sufficiently concerned with the use of these anchors to recommend that further work be done to see if an alternative extraction method can avoid spalling.  We note Bolt Products recommend cutting the head off, and then core drilling the rest of the anchor out.  Because we currently recess our anchors it appears to us that it will be difficult to cleanly cut the head off, so we are unsure that their method will work for us.

We will write the work up with photographs and videos in due course.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 25, 2014, 11:07:36 am
Just out of interest and I'm sure it will be in your write-up but was the spalling parallel or normal to the bedding and to what depth (roughly) did the spalling extend?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 25, 2014, 03:32:55 pm
Easy peasy resin anchor removal.

http://www.resinanchor.co.uk/5.html (http://www.resinanchor.co.uk/5.html)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 25, 2014, 03:37:29 pm

 :clap2:

does the circular contact point around the circumference prevent the spalling??

Has it been tested on BP bolts yet??

Did you drill out any resin first ??
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 25, 2014, 04:03:54 pm
Yes, nice one Simon  :thumbsup:
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 25, 2014, 04:05:27 pm

 :clap2:

does the circular contact point around the circumference prevent the spalling??

Has it been tested on BP bolts yet??

Did you drill out any resin first ??

No drilling, no heating just pulling.

I don't own any BP anchors but if somebody left some anchors lying around for no apparent reason without any labels do you think I would be justified in pulling them out in order to test my puller in the interest of all cavers?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 25, 2014, 04:10:08 pm
I don't think so without asking whoever placed them, they could be part of some other program. Why not just get together with Bob Mehew and do some tests?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 25, 2014, 04:25:41 pm
I don't think so without asking whoever placed them, they could be part of some other program. Why not just get together with Bob Mehew and do some tests?

So you don't think I would be doing a public service by removing some of the many anchors which detract from an oft-frequented public open space near Ingleton. If the people that installed them didn't want them touching I think they would have labelled them.

The answer to your question is that I probably will do sometime but we don't know when.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 25, 2014, 04:28:49 pm
Probably only just fits over a BP anchor, measuring by eye it is 48mm but I am sure that would squash. The dmm are slightly bigger, but I am sure with a different tube it could be used.

What is the max force? Over 60KN can be needed for BP.

It would be good to test it on the different anchors in play
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 25, 2014, 08:01:15 pm
I think
http://www.resinanchor.co.uk/5.html (http://www.resinanchor.co.uk/5.html)
is one of a number of Singing River anchors put in a large slab by us some years ago on the middle bench of the quarry.  Please do not touch all the anchors on the lower bench; some are used by local OECs for wheel chair users.  ( But I don't know which.)

Was the thread HT?  And can I borrow it for 6 & 7 Dec if you are not free?

Just out of interest and I'm sure it will be in your write-up but was the spalling parallel or normal to the bedding and to what depth (roughly) did the spalling extend?
Both!  Several cm.  One possible explanation is blast damage since they were both 'quarry' boulders.  And as has been pointed out to me, a fault is likely to put a fair amount of damage into the local rock.   
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 25, 2014, 10:03:12 pm

Both!  Several cm.  One possible explanation is blast damage since they were both 'quarry' boulders.  And as has been pointed out to me, a fault is likely to put a fair amount of damage into the local rock.


Thanks
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 25, 2014, 11:34:35 pm
I think
http://www.resinanchor.co.uk/5.html (http://www.resinanchor.co.uk/5.html)
is one of a number of Singing River anchors put in a large slab by us some years ago on the middle bench of the quarry.  Please do not touch all the anchors on the lower bench; some are used by local OECs for wheel chair users.  ( But I don't know which.)


It was a Singing Rock anchor on the sloping slab. There are several anchors on that slab in various states, some bent over, partly pulled out or partly broken off but all obviously of no use.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 25, 2014, 11:44:22 pm
Andrew Atkinson and myself carried out 4 extractions of Bolt Product anchors on Sunday...............  In contrast, the other bolder showed massive spalling, covering roughly 50cm by 40cm and 30cm by 30cm of the surface around the hole.  (We had decided to not drill out surplus resin for these two anchors, but consider that this made no difference to the extensive spalling witnessed.) 


'Spall' is a word used for small chips of rock. What you have seen is not spalling, it is 'cone failure' originating from the point of maximum mechanical bond about 25-30mm below  the surface.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 26, 2014, 01:22:16 am
I would define "spalling" in this way:

"Spalling is a common mechanism of rock weathering, and occurs at the surface of a rock when there are large shear stresses under the surface. This form of mechanical weathering can be caused by freezing and thawing, unloading, thermal expansion and contraction, or salt deposition." 
(From wikipedia.)

It is often used to describe the process where brickwork faces get "spalled off", or in concrete (often where carbonation has reached the reinforcing, causing corrosion expansion).
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 26, 2014, 09:06:23 am
I would define "spalling" in this way:

"Spalling is a common mechanism of rock weathering, and occurs at the surface of a rock when there are large shear stresses under the surface. This form of mechanical weathering can be caused by freezing and thawing, unloading, thermal expansion and contraction, or salt deposition." 
(From wikipedia.)

It is often used to describe the process where brickwork faces get "spalled off", or in concrete (often where carbonation has reached the reinforcing, causing corrosion expansion).

There are two different processes described there. The first process is more commonly called exfoliation. Exfoliation might occur when a resin anchor is pulled out but what Bob has seen is not exfoliation. Exfoliation is one mechanism that could produce what might be called spall but there are an infinite number of ways. Chiseling might also produce spall; it might produce it at the point of the chisel where small fragments of rock break off and it might produce it at the head of the chisel where small fragments of steel break off. You could use the term spalling for what Bob has seen but in my opinion it is bad use of the word and cone failure is a more accurate term. I'm sorry if this sounds pedantic but it is important to understand the process of what is happening not what the product is; the product might be called spall but the process is definitely cone failure.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 26, 2014, 10:42:41 am
Am  I being thick here? I cannot understand why anyone would want to pull a perfectly good anchor out of it's placement, except for strength tests, etc. Surely any anchor being removed will already be loose and that would be the only reason for it to be replaced. So it's going to be loads easier to pull out anyway surely? Or am I missing something?  :-\
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bottlebank on November 26, 2014, 10:49:58 am
Am  I being thick here? I cannot understand why anyone would want to pull a perfectly good anchor out of it's placement, except for strength tests, etc. Surely any anchor being removed will already be loose and that would be the only reason for it to be replaced. So it's going to be loads easier to pull out anyway surely? Or am I missing something?  :-\

They don't last for ever, sooner or later many will need replacing.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 26, 2014, 11:01:54 am
From a conservation point of view the question is: should we install ANYTHING that we can't remove with minimal impact on the cave?

We might not expect to replace them but who knows what will happen in the future? Apart from unexpected corrosion and wear and collapses and the like meaning that bolts may need moving, there is a video on YouTube of a guy climbing up a glass fronted building using "geko" pads, if that technology develops we might not even be doing SRT in 30 years time.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 26, 2014, 01:00:28 pm
'Spall' is a word used for small chips of rock. What you have seen is not spalling, it is 'cone failure' originating from the point of maximum mechanical bond about 25-30mm below  the surface.

I would define "spalling" in this way:

"Spalling is a common mechanism of rock weathering, and occurs at the surface of a rock when there are large shear stresses under the surface. This form of mechanical weathering can be caused by freezing and thawing, unloading, thermal expansion and contraction, or salt deposition." 
(From wikipedia.)

It is often used to describe the process where brickwork faces get "spalled off", or in concrete (often where carbonation has reached the reinforcing, causing corrosion expansion).

There are two different processes described there. The first process is more commonly called exfoliation. Exfoliation might occur when a resin anchor is pulled out but what Bob has seen is not exfoliation. Exfoliation is one mechanism that could produce what might be called spall but there are an infinite number of ways. Chiseling might also produce spall; it might produce it at the point of the chisel where small fragments of rock break off and it might produce it at the head of the chisel where small fragments of steel break off. You could use the term spalling for what Bob has seen but in my opinion it is bad use of the word and cone failure is a more accurate term. I'm sorry if this sounds pedantic but it is important to understand the process of what is happening not what the product is; the product might be called spall but the process is definitely cone failure.


I disagree with describing it as cone failure.  I would define cone failure as reaching down to the full depth of the anchor such that the anchor is then free.  Neither case let go to that extent in that the anchors still required considerable force to fully extract.  If you wish to define spalling as limited to small chips with no influence on the strength of the anchor, then what word do you wish to use for larger sized loss?  Exfoliation sounds good to me.

Whilst the depth corresponds to your postulate that a significant feature of the BP anchor is the shift from a straight shaft to twist, the anchor was still holding post start of 'spalling'.  Typically I failed to record pertinent data on the video around the key episodes such as strength so am unable to say if the force peaked after the 'spalling' started.  What is clear is that the anchor had hardly started to travel out of the hole and took a fair force to extract it all the way.

Do we need to agree a dictionary before starting a discussion?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 26, 2014, 01:17:05 pm
Am  I being thick here? I cannot understand why anyone would want to pull a perfectly good anchor out of it's placement, except for strength tests, etc. Surely any anchor being removed will already be loose and that would be the only reason for it to be replaced. So it's going to be loads easier to pull out anyway surely? Or am I missing something?  :-\

You're not missing anything. We wouldn't want to pull out a perfectly good anchor. We might want to pull out anchor if there was doubt about it's integrity for a number of reasons. Thebitterend has it right, we don't know what might happen in the future. It's about sustainability and the principal is not doing things which can't be undone. We can't go into caves with no environmental impact but we can do things to minimise it by making sure that anchors can be removed and the hole reused and that the hole is as small as possible.

Some people have not appreciated the amount of development work that has gone into the design of my anchor and that sustainability was one part of the design criteria from the start. It is very important that the load is applied at the bottom of the hole. The shank of my anchor is tapered to avoid loading the rock nearer to the surface. No other anchor design does what my design does.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 26, 2014, 01:56:00 pm
'Spall' is a word used for small chips of rock. What you have seen is not spalling, it is 'cone failure' originating from the point of maximum mechanical bond about 25-30mm below  the surface.

I would define "spalling" in this way:

"Spalling is a common mechanism of rock weathering, and occurs at the surface of a rock when there are large shear stresses under the surface. This form of mechanical weathering can be caused by freezing and thawing, unloading, thermal expansion and contraction, or salt deposition." 
(From wikipedia.)

It is often used to describe the process where brickwork faces get "spalled off", or in concrete (often where carbonation has reached the reinforcing, causing corrosion expansion).

There are two different processes described there. The first process is more commonly called exfoliation. Exfoliation might occur when a resin anchor is pulled out but what Bob has seen is not exfoliation. Exfoliation is one mechanism that could produce what might be called spall but there are an infinite number of ways. Chiseling might also produce spall; it might produce it at the point of the chisel where small fragments of rock break off and it might produce it at the head of the chisel where small fragments of steel break off. You could use the term spalling for what Bob has seen but in my opinion it is bad use of the word and cone failure is a more accurate term. I'm sorry if this sounds pedantic but it is important to understand the process of what is happening not what the product is; the product might be called spall but the process is definitely cone failure.


I disagree with describing it as cone failure.  I would define cone failure as reaching down to the full depth of the anchor such that the anchor is then free.  Neither case let go to that extent in that the anchors still required considerable force to fully extract.  If you wish to define spalling as limited to small chips with no influence on the strength of the anchor, then what word do you wish to use for larger sized loss?  Exfoliation sounds good to me.

Whilst the depth corresponds to your postulate that a significant feature of the BP anchor is the shift from a straight shaft to twist, the anchor was still holding post start of 'spalling'.  Typically I failed to record pertinent data on the video around the key episodes such as strength so am unable to say if the force peaked after the 'spalling' started.  What is clear is that the anchor had hardly started to travel out of the hole and took a fair force to extract it all the way.

Do we need to agree a dictionary before starting a discussion?
With the BP anchor fragmentation, spalling, disintegration. smashing or breakage of the rock occurs emanating from the point of maximum mechanical bond at the start of loading and that point is where the twists start. The fact that it still has considerable mechanical bond after the initial cone failure does not matter because the cone failure has already rendered the hole unable to be reused.

Cone failure can occur at any point down the hole. With a through-bolt if cone failure occurs it will occur at the point of maximum mechanical bond which is where the taper is and a short distance from the bottom of the hole. It will leave  the bottom part of the hole intact. The difference between that cone failure and the BP cone failure is the proportion of the hole that is left intact.

'Exfoliation' has a specific meaning in geomorphology and refers to breaking off of sheets - from the Latin folio. Exfoliation occurs to limestone and other rocks when the surface has altered by exposure to the elements. With limestone the exfoliation typically is about 2-3mm deep. In American geomorphological journals 'spalling' is sometimes used instead of 'exfoliation'. Spalling is also used in engineering to describe the breaking off of fragments of any material and does not have a very specific definition.

Can we stop getting hung up on words. The main point is that you can't get a BP anchor out without breaking the rock.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mmilner on November 26, 2014, 02:06:51 pm
You're not missing anything. We wouldn't want to pull out a perfectly good anchor. We might want to pull out anchor if there was doubt about it's integrity for a number of reasons. Thebitterend has it right, we don't know what might happen in the future. It's about sustainability and the principal is not doing things which can't be undone. We can't go into caves with no environmental impact but we can do things to minimise it by making sure that anchors can be removed and the hole reused and that the hole is as small as possible.

Some people have not appreciated the amount of development work that has gone into the design of my anchor and that sustainability was one part of the design criteria from the start. It is very important that the load is applied at the bottom of the hole. The shank of my anchor is tapered to avoid loading the rock nearer to the surface. No other anchor design does what my design does.

Thanx Simon. That makes perfect sense, Hole as small as possible. Load applied at the bottom of the hole. I don't like the idea of having to drill 16 or 18mm holes. A 12mm would be much better and would take less power to drill. The tapered design seems a good idea too, when a load is applied it would tend to grip more tightly in the hole as well wouldn't it!  :thumbsup:
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 26, 2014, 02:17:31 pm
My design is quite sophisticated and took months of development work. I has several tapers and it would take a long time to fully explain it all. As well as not loading the rock near the surface it also has a taper-lock effect which takes place as it starts to move under load.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 26, 2014, 03:53:54 pm
I am not going to try and explain why I think your view on words is wrong, save to comment that both of us felt one 'spalled' hole was potentially OK to reuse after drilling the hole a bit deeper.  In part you need to see the photos.

The main point is that you can't get a BP anchor out without breaking the rock.
Not true!  We got 2 out of 4 out without breaking the rock.  We were deliberately not placing our load directly around the hole which you ingenious device does and which may well stop rock breaking.  We also have a possible route of lifting the head by a lever, cutting the head off and then core drilling the rest out.

Also if I recall correctly, you have only tested your anchors in one area of limestone which was not a quarry nor on a fault.  So it might be solely a rock related problem rather than a design of anchor problem. 
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: bograt on November 26, 2014, 11:26:42 pm
We also have a possible route of lifting the head by a lever, cutting the head off and then core drilling the rest out.

I imagine you are thinking about core drilling round the old anchor to get it out, then inserting a fresh resin anchor into the hole thus produced?
 Have you any thoughts on removing the old resin left behind in the hole? although the bond between this and the rock might be adequate, how about the bond between the new resin and the old stuff left with a smooth surface by core drilling?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 27, 2014, 08:17:40 am

Also if I recall correctly, you have only tested your anchors in one area of limestone which was not a quarry nor on a fault.  So it might be solely a rock related problem rather than a design of anchor problem.

You've forgotten that I've tested my anchor in weathered gritstone, that the field I've done most of my testing in has been quarried in parts and that my anchor was tested in several planes in quarried faces and boulders all with the Rawl resin. When I changed to Fischer I also purposely changed the method and did all the tests in one bed so I could eliminate as much as possible the effects of variation in the physical properties of the rock. Perhaps I need to explain that in the test report on my website. I have plans to test at other sites.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on November 27, 2014, 09:03:41 am
Have you any thoughts on removing the old resin left behind in the hole? although the bond between this and the rock might be adequate, how about the bond between the new resin and the old stuff left with a smooth surface by core drilling?
The theory is that you go back in afterwards with a rotary percussion drill to roughen up the sides of the hole.

PS Sorry, getting out the report on last Sunday's work is taking me longer than expected.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 27, 2014, 09:10:03 am
Core drilling around a BP anchor would leave a hole of at least 22mm diameter and probably bigger.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Badlad on November 27, 2014, 11:14:37 am

Hand held coring is not likely to leave a very smooth hole.  My experience of coring out for pipes and conduits through walls is that you wobble around leaving circular grooves in the hole.  What is likely to be more of a problem is following the same line as the original hole even if you're using the same diameter bit.  A larger diameter bit will probably make it even harder.  The shape and style of the hole, any remaining resin, it's surface area and shape will introduce variables which are going to be difficult to allow for in any testing.  In practice coring may be be a problematic option.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 27, 2014, 11:56:57 am
You would core drill part way then still need a puller. All done hanging on a rope. Not very practical.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: bograt on November 27, 2014, 01:25:51 pm
You would core drill part way then still need a puller. All done hanging on a rope. Not very practical.

I suspect the principle of core drilling is based upon removal of the loop head before drilling, how are you going to attach the puller?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 27, 2014, 01:51:27 pm
You would core drill part way then still need a puller. All done hanging on a rope. Not very practical.

I suspect the principle of core drilling is based upon removal of the loop head before drilling, how are you going to attach the puller?

Errrrr,, oh yes! So you would have to core drill 100mm deep hanging on a rope whilst squirting water from a squeezy bottle.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 27, 2014, 11:09:12 pm

FYI

The BMC did a lot of testing of resin bolts over the last few years. They plumped for the BP bolt in the end. 

https://www.thebmc.co.uk/bmc-better-bolts-campaign (https://www.thebmc.co.uk/bmc-better-bolts-campaign)

However, my point is that they tried (and I mean went out, bought the kit and tried it) core drilling around an old spit. They found that it was just too technically and practically difficult to warrant any further experimentation.   
Remember a spit is only 12mm in diameter and only about 20mm deep.  If this was just too much of a pain in the ass to consider. Coredrilling something in the region of 18mm diameter and 150mm deep, whilst dangling.  Forget it.
There is also the issue that the 'back' of the hole will still be attached.  At least with a spit, you can possibly still screw a hanger to it to pull it.  If you chopped the eye off, then how, after core drilling, are you going to extract the 'plug' if its still attached at the back.
I just don't think its even worth the effort of typing any more on the topic of core drilling, its a bit of a non starter.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 27, 2014, 11:42:52 pm
People dismiss things too easily ;D

I successfully replaced a hand placed spit today, after trying it on Saturday. Just got the photos and stuff back after leaving them behind, but will deal with that tomorrow.

It takes less than 5 mins, the only hard part is getting the spit out of the core after, more tedious than hard. It leaves a 16mm hole, that I roughened up with a drill.

You will need one of these, well probably more than one, but so far I  have only done 2 spits, so that is a matter of more testing

http://www.ebay.co.uk/itm/271381875583 (http://www.ebay.co.uk/itm/271381875583)
Select the 16mm one
Guess this link will break in time, so it is a 16mm diamond core bit (does not say a make or anything, and came in a white box, but of £7.16 it seems great)

Quaking anyone?

Tend to agree that bigger will be more of a pain, and do not think that it is a practical one for a BP anchor, especially if there is an alternative that does come out.


Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 28, 2014, 12:08:03 am
Thanks Andrew. That is what I expected. It is practical to core drill round a Spit but not easy.

My puller will pull out most resin anchors but not a BP.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Antwan on November 28, 2014, 07:01:51 am
My puller will pull out most resin anchors but not a BP.
Good news for people hanging on them at least.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: TheBitterEnd on November 28, 2014, 07:41:01 am

There is also the issue that the 'back' of the hole will still be attached.  At least with a spit, you can possibly still screw a hanger to it to pull it.  If you chopped the eye off, then how, after core drilling, are you going to extract the 'plug' if its still attached at the back.

I've done this with big cores in reinforced concrete, you just hammer a small chisel down the side and break the core up. If you are lucky it comes out in one.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: MarkS on November 28, 2014, 01:09:42 pm
My puller will pull out most resin anchors but not a BP.

It's a neat bit of kit. Sorry if this has been answered already, but is that because the BP anchor is too large, or too strong? Can it pull out an IC anchor?
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 28, 2014, 08:05:07 pm
I haven't tried the removal tool on an IC anchor but I'm confident it would pull one out.

Some BP anchors would require more force than the tool can exert. BP anchors have pulled out at loads from 24 to 63kN.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 28, 2014, 10:41:04 pm
People dismiss things too easily ;D
I successfully replaced a hand placed spit today, after trying it on Saturday. Just got the photos and stuff back after leaving them behind, but will deal with that tomorrow.
It takes less than 5 mins, the only hard part is getting the spit out of the core after, more tedious than hard. It leaves a 16mm hole, that I roughened up with a drill.

Nice one...  ;D and good to hear.  I have to admit to not having tried it myself, just having taken the word of someone who had, (dan from the bmc). 

Its not so much of an issue in the peak, as most of the popular routes were done back in the 90's with DMMs by Ralph et al  :bow:

I can think of one or two spots that still have spits (and no doubt others will add more) but I doubt we'll bother with core drilling, just find a nearby placement as we did in winnats head last year.

How do folks suggest we remove the many 12mm stainless through bolts that are commonplace on many routes these days.  Folks rarely 'overdrill' them as they should, so they cant be pushed deeper and resin placed in the hole to mask it. 

Extraction will almost certainly result in spalling and rock damage due to the mechanics of a through bolt (any one tried and have empirical evidence ??)

Only way I can see is to pull outwards by hand, grind off then push back in and resin over.

Winnats had numerous 'studs' remaining now.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: bograt on November 28, 2014, 11:33:38 pm
Seems like there is a need for definitions here, What is the difference between 'spits' and 'studs'? etc.

My interpretation of 'spits' is the self-drilling anchors, about 12mm OD, with an 8mm thread and a 13mm OD spanner to drive them, hammered into the hole to drive the wedge in. I have fitted a lot of these in obscure locations to allow access to non-viable locations. (usually at the top of dubious maypoles!). There is not a problem removing these with the use of an oversized bolt engineered correctly, the question of the removal of the various kinds of Rawlbolts depends upon which kinds they are, and can usually be resolved by the application of a hammer in the right place and a bit of furkuling in the right place.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: SamT on November 29, 2014, 12:15:12 am
crikey...basic lesson in terminology.

spit
(http://www.starlessriver.com/shop/images/large/spit-self-drill-rock-anchor_LRG.jpg)
(https://www.hilti.co.uk/medias/sys_master/images/h73/9086711726110/30334_APC_460x260.jpg)
used in conjunction with
(http://www.starlessriver.com/shop/images/petzl%20vrillee%20hanger.jpg)

either self drilled, or drop in (like the hkd drop in ones with integral wedge)
leaves a 'female' threaded hole, flush with the rock surface. you use a 'bolt' to screw a hangar onto the spit.

Thru bolt..
(http://inglesport.com/images/products/_large/raumerm10l%207.jpg)
leaves a protruding 'male' thread or 'stud' onto which you slide a hanger
(http://inglesport.com/images/products/_large/coeur_5.jpg)
and screw on your own 'nut'

Multi Monti, titan, screw in
(http://img.edilportale.com/products/prodotti-12862-relb45b03f7-979d-4a6b-a057-ff9dcde37e6a.jpg)
'self tapping' screw in anchor. works like an ice screw, but in limestone.  Can be re-used. leaves a hole

Pretty sure we're all familiar with glue in anchors - P bolts, BP bolts, IC anchor etc etc
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: bograt on November 29, 2014, 08:56:22 am
 :thumbsup:  :lol: Thanks for that Sam  :thumbsup:

The bog standard spit can be removed with a long high-tensile bolt with the end cm or so of thread ground off to force the wedge out and an extended tommy bar socket.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 29, 2014, 09:06:53 am
Only hand spits (probably what you mean by bog standard) and only if the thread is still good, and even then not reliably, the thread often (limited trials) fails.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 29, 2014, 09:09:02 am
:thumbsup:  :lol: Thanks for that Sam  :thumbsup:

The bog standard spit can be removed with a long high-tensile bolt with the end cm or so of thread ground off to force the wedge out and an extended tommy bar socket.

Not when the threads have gone.

One of you is confusing the terminology. I always reserved the word Spit for self-drilling genuine Spits. Sam included all drop-ins which is OK because Spit also make drop-ins. Many people are aware of the confusion and take account of it.
http://www.toolstation.com/shop/p68019?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=ysH9pTyq&pcrid=46334671103&gclid=CM21tNi3n8ICFanMtAodjRgAeA (http://www.toolstation.com/shop/p68019?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=ysH9pTyq&pcrid=46334671103&gclid=CM21tNi3n8ICFanMtAodjRgAeA)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 29, 2014, 11:24:43 am
I think some people would call these type of drop-ins "spits" too - not always possible to tell them apart from a self drill when in the cave.

https://www.hilti.co.uk/anchor-systems/flush-anchors/r4581 (https://www.hilti.co.uk/anchor-systems/flush-anchors/r4581)

The wedge is "captive" in these and a "setting tool" is used to drive the wedge in.

As Simon points out, the company "Spit" makes a wide range of anchors to add to the confusion!  http://www.itwcp.co.uk/products/spit/mechanical-anchors/ (http://www.itwcp.co.uk/products/spit/mechanical-anchors/)
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 29, 2014, 11:29:55 am
I can think of one or two spots that still have spits (and no doubt others will add more) but I doubt we'll bother with core drilling, just find a nearby placement as we did in winnats head last year.

Yes that is generally what has been done, I have done it myself, but should we not be thinking about conservation and protecting a limited resource?
Would you leave a chocolate wrapper in a cave? I hope not, does it make it any better if you cover the chocolate wrapper with a rock? Just a thought.

I have got round to making videos and images of a reasonable size

(http://wotcc.org.uk/Anchors/SpitRemoval/CoreDrillSpit.jpg)

A really dull video of it can be seen at http://wotcc.org.uk/Anchors/SpitRemoval/ (http://wotcc.org.uk/Anchors/SpitRemoval/)

Just below the image, the slightly more interesting bits are at 3:49 and 4:41

For those of you who have not fit a BP bolt, I also videoed that as well, the hammering of it to get it into the whole is at about 0:44

http://wotcc.org.uk/Anchors/AnchorPlace/ (http://wotcc.org.uk/Anchors/AnchorPlace/)

Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 29, 2014, 03:29:33 pm
I started installing anchors in caves in the early 1980's and I was always led to believe that 'Spits' were the self drilling anchors that, once installed, you would break off the top section of the bolt with the special driver and then install a traditional hanger plate. The break, unfortunately, wasn't always clean and could damage the driver and/or the hanger. I've never actually seen one but i'm sure there is a photograph of one in a caving book. Not one I have unfortunately. I think you might have to be over 50 to remember them.

I think it's just been a continuing tradition to call all drop-in type anchors 'Spits'.

The videos of removing an old self drilling anchor and re-installing the new 'Twisted' anchor have me confused. Is that not a diamond core drill? I thought the recommendation was not to use a diamond drill bit for the new anchors. I assume the hole is then 'roughened' with a standard 16mm drill bit?

The removal did look easy though.

However, when the bolt is in anything other than the horizontal and you haven't got a coolant pool and instead of being stood up in your casual clothes on a nice day, you will be trussed up with all your caving gear whilst suspended from another bolt with a big heavy drilling machine in one hand, at arms reach and water trickling down the back of your neck through the gap in your oversuit!!!   

Not so easy then.

It would have been nice to see a fully installed anchor with all the excess resin removed from the rock around it and, in particular, around the lower inside section of loop where ultra-lightweight alloy carabiners and 9mm ropes (as referred to in another thread) may be attached directly. Excess resin that is not removed from here and allowed to set hard could, subject to a dynamic load, lead to the catastrophic failure of the carabiner or, more likely, the rope. Remember the tests carried out to determine 'Full Strength' of lightweight connectors and ropes use a 10mm round bar, not a jagged piece of hardened resin.

Mark

   
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 29, 2014, 04:13:10 pm
Yes it was in a pool of water, first go, so not sure how hard it was going to be, so to be safe dud it in a puddle. I did not actuality place an anchor in the hole, just showed it in the video to show it would work.
Since the video, I have done one in a cave that on a wall, very little water was needed. In this hole I did roughen after with a normal drill.

As for placing the anchor, yes leaving to much resin in the anchor eye makes it difficult to use, the resin around the back of the eye is needed to stop rotational failure. The small bits inside and nearly impossible to wipe out when wet, but when as thin as shown in the video it breaks off on first use leaving a clean eye, hopefully not leading to the problems you gave described.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Simon Wilson on November 29, 2014, 04:42:03 pm
I started installing anchors in caves in the early 1980's and I was always led to believe that 'Spits' were the self drilling anchors that, once installed, you would break off the top section of the bolt with the special driver and then install a traditional hanger plate. The break, unfortunately, wasn't always clean and could damage the driver and/or the hanger. I've never actually seen one but i'm sure there is a photograph of one in a caving book. Not one I have unfortunately. I think you might have to be over 50 to remember them.

I think it's just been a continuing tradition to call all drop-in type anchors 'Spits'........................

 

The break-off ones were earlier and were called Redheads - horrible things - even worse than Spits.
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: cavermark on November 29, 2014, 04:51:19 pm

The videos of removing an old self drilling anchor and re-installing the new 'Twisted' anchor have me confused. Is that not a diamond core drill? I thought the recommendation was not to use a diamond drill bit for the new anchors. I assume the hole is then 'roughened' with a standard 16mm drill bit?



See Replies 109 and 111 - Badlad apparently "wobbles around" when coring - don't know if he means the drill bit or that he's had a lunchtime session first...
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Mark Wright on November 29, 2014, 06:48:18 pm
Redheads. Thanks for that reminder Simon. You obviously do have to be over 50.

You wouldn't want to wobble much with such little clearance between the inside of the drill and the old anchor, particularly near the spayed out bit at the bottom. I bet it would kick a bit if the core drill snagged it.

Mark
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on November 29, 2014, 06:52:07 pm
The dimond appears to drill through it not snag, marks where I did it further up are visible on the photo.

Maybe this technique should only be used after lunch in the Hunters  ;D
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on December 11, 2014, 10:55:09 am
The observations from the placing and then removal of BP anchors at FCQ are now available

wotcc.org.uk/Anchors/BPAnchorPull/ (http://wotcc.org.uk/Anchors/BPAnchorPull/)

Sorry I do not go in for dressing things up, so it is very simple but efficient html
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: mikem on September 19, 2018, 08:14:07 am
Is the document linked in last post still available elsewhere?

I was wondering if any tests had been done on resin bolts without glue, as that would model worst case fixing scenario ? (Must confess I haven't reread all 6 pages).

Also, from holes that are slightly too big, as would like to know how much wear removable bolts can cope with?

Mike
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: Bob Mehew on September 19, 2018, 08:37:26 pm
Does http://british-caving.org.uk/wiki3/doku.php?id=equipment_techniques:anchor_scheme (http://british-caving.org.uk/wiki3/doku.php?id=equipment_techniques:anchor_scheme) provide some useful information on the topic?  Also IC anchors has good stuff, see the testing and removal pages at http://www.resinanchor.co.uk/ (http://www.resinanchor.co.uk/).

I have PMed you as well.

Bob
Title: Re: Merged topic - Spit and BP bolt removal/replacement
Post by: andrew on September 20, 2018, 12:14:10 pm
I have fixed the links above