Author Topic: Fabrication: Hanger with 10mm bolt hole  (Read 782 times)

Online alastairgott

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Fabrication: Hanger with 10mm bolt hole
« on: May 04, 2021, 11:16:24 pm »
A bit of an odd request, I need some hangers for lifting boulders/rocks. Only 2 or three at the moment, but they don’t need to be petzl or dogs bollocks. Just angle iron will do.


The thing is I need the bolt hole to be 10mm, I cocked up years ago when trying out bolting, bought dewalt screwbolts (wrong brand, apparently) and I also bought for an 8mm hole, but dipstick here didn’t realise that the thread would naturally be bigger than 8mm and therefore not fit hangers with an 8mm hole.


I want to pull some rocks out of a hole (some approaching 1m in size). As it’s only surface at the moment it would be great to have a hanger that I can use to get the rocks out of the way. If I need to haul a greater distance than 2-4m then I’ll shift to other methods.


I already have half a dozen petzl hangers and throughbolts for them, but the idea of using up the dewalt screwbolts is more tempting and eco friendly.


Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #2 on: May 05, 2021, 08:14:38 am »
They’re a good price! Thanks sam. I’ll order a couple.

Offline sinker

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #3 on: May 05, 2021, 10:51:40 am »
I remember Dave L fabricating some a few years ago, cut and shaped out of stainless angle iron.
They turned out OK but the work/time involved along with the cost of the materials and INOX cutting discs was ridiculous. Far cheaper to buy them, but still a useful exercise if someone happened to give you a load of stainless angles and cutting discs free of charge and you had a few evenings spare.

 :thumbsup:
Ah, well, now, you see...erm...

Offline AlexR

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #4 on: May 05, 2021, 12:41:48 pm »
Hey Alastair, just sent you a message. If you haven’t already done so, don’t buy any hangers! I can sort you out with some  :)

Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #5 on: May 05, 2021, 12:57:24 pm »
Cheers Alex!

Offline Cantclimbtom

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #6 on: May 05, 2021, 01:07:58 pm »
I can post you 2 x petzl 12mm hangers and 2 x 10mm washers if you want... (pm me if you are still looking)
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Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #7 on: May 05, 2021, 01:26:09 pm »
I’ve had offers of about 56 hangers. Thank you to all that have got in touch, I’ll choose closest geographically first which will be Alex.


(I only needed two or three :) )

Offline Cantclimbtom

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #8 on: May 05, 2021, 01:42:53 pm »
Pleased to hear you will be able to use "real" hangers. Quite a few years ago I needed (well wanted..) 2 hangers same-day, so I chopped 1.5" off a sticky out bit of angle on the side of my car run up ramps (matching bit on both ramps). I drilled a 10mm and a 12mm hole in each and used as hangers to bolt at the top of an old railway viaduct (in a discrete place low down, inside the parapet wall), to top rope a climb. They were BL00DY AWFUL hangers. I advise against home mades
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Offline pwhole

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #9 on: May 05, 2021, 06:22:11 pm »
Isn't a 1m boulder approaching the minimum breaking load for a 10mm bolt hanger? Limestone is approx. 2.2 tons per cubic metre. I'm not at home this week, but I'm sure my Raumer 10mm hangers are 26kN. Give the potential resistance/friction that might be encountered pulling rocks out of a hole, is this system strong enough? Especially using screws on a tensile load - that's not a lot of steel thread pulling a ton or two. Unless I'm completely misunderstanding it.

Offline Mark Wright

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #10 on: May 05, 2021, 06:42:46 pm »
Just to add to pwhole's comments, many years ago Richard (Terry Fuckwit) Greenslade and I did some monster bolt climbs on the Emley Moor TV mast.

We were using 10mm S/S drop-in anchors and we managed to snap a few of them during axial testing with 10mm Petzl hangers due to the levering forces applied. They were breaking at well below 6kN so I'd be careful trying to lift those sorts of weights with this type of hanger.

You might be better off using some sort of ring hanger that allows a direct pull.     

Mark

Online Fishes

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #11 on: May 05, 2021, 06:52:18 pm »
I generally use the Screwbolts with eyes which don't need hanger plates. I must have pulled hundreds of boulders out of  chokes with these things. Seeing how much force you can apply in this application gave me the confidence to use them in exploratory rigging.

If you are wanting to pull something really big then you can use multiple anchors but then you need something like a big Tirfor to pull with. I've used to move things that weigh several tons but they are too big, heavy and awkward for general use. You are also going to need something bombproof to attach the Tirfor to.

Offline sinker

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #12 on: May 05, 2021, 07:04:36 pm »
I generally use the Screwbolts with eyes which don't need hanger plates. I must have pulled hundreds of boulders out of  chokes with these things. Seeing how much force you can apply in this application gave me the confidence to use them in exploratory rigging.

If you are wanting to pull something really big then you can use multiple anchors but then you need something like a big Tirfor to pull with. I've used to move things that weigh several tons but they are too big, heavy and awkward for general use. You are also going to need something bombproof to attach the Tirfor to.

Or a Z-rig pully system on 2 hangers?
Half the load onto the hangers and effectively halving the weight of the boulder.
Use a STOP or a CROLL or something as a brake/arrestor so that you can hold the load and take a breather.

With a cat's cradle of 3 or 4 slings around the boulder?
Or drill an eye bolt into the boulder and lift it that way.

Ah, well, now, you see...erm...

Online Fishes

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #13 on: May 05, 2021, 07:27:23 pm »
Z rigs are OK for lightish loads but if you apply enough force to lift anything heavy then the jammer with split the sheath of the rope, cut into the rope, destroy the jammer itself or combination of those.

Offline Cantclimbtom

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #14 on: May 05, 2021, 08:17:02 pm »
If the boulders were 1 metre cubes and needed a big sized tirfor, I think I'd want to consider using some expanding (expansive?) grout and come back the following weekend to deal with the broken bits
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Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #15 on: May 05, 2021, 08:43:19 pm »
I was guessing at the rocks size, so could be over egging it a little bit. "The fish was this big!" It might actually be half a meter on the longest axis  :lol: :clap2:

Fishes, ill look up these screwbolts with rings as they sound good!

To get going I need to be able to shift some bigger rocks on the surface, but being able to release some gravity on them should help. Then I can start to think about others and whether I split them.

It's not in an isolated spot being 10-15 mins from a parking spot and not far from the nearest town.

If need be I'll:
-borrow a shunt of someone to stop the rope being chopped
-Grab some slings as sinker suggests
-Use multiple anchors as fisher suggests with the club tirfor.
-Add some ground anchors into the mix for the static part of the haul with a "big knot". (2 hangers + 3 ground) should even out the load, if it needed it.

Then if all looks good I'll move onto employing other things like scaff tripods, buckets, cargo nets. But at the moment I'm only at the stage of ooh I like the look of that I'll pull some more stuff out.

Online Fishes

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #16 on: May 05, 2021, 08:53:12 pm »
Slings are OK (but less secure in by experience than Screwbolts) but you need access around and under the block. If you are using Screwbolts then generally you can pull it out without digging around it - just pop one or two bolts in and apply some pull, then jiggle it around with a pry bar until it comes free. This makes for much faster and easier digging.

Offline sinker

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #17 on: May 05, 2021, 09:05:24 pm »
Z rigs are OK for lightish loads but if you apply enough force to lift anything heavy then the jammer with split the sheath of the rope, cut into the rope, destroy the jammer itself or combination of those.

That's why I said "Use a STOP or a CROLL or something....."  ;)
Ah, well, now, you see...erm...

Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #18 on: May 05, 2021, 09:12:15 pm »
I know what you're both getting at :)

I'll be reducing/spreading the load so no sheath splitting with the pulling device. and i'll be using a device to help me/others rest from hauling :)

Offline pwhole

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #19 on: May 05, 2021, 09:36:41 pm »
Ah, the 'others'. I wondered when they'd get mentioned. I'd better get some padded trousers ;)

Offline Mark Wright

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #20 on: May 05, 2021, 09:41:24 pm »
Why don't you just cap it into small lumps and pull it out in easily manageable bucket loads?

Mark

Online PeteHall

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #21 on: May 05, 2021, 10:25:47 pm »
Why don't you just cap it into small lumps and pull it out in easily manageable bucket loads?

Mark

Not always appropriate for a surface dig?  :shrug:

Online alastairgott

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #22 on: May 05, 2021, 10:55:19 pm »
I’m sure a plan will form, I can borrow capping gear (and have done from chief of “the others”  :smartass:  before ) so it’s available.

Offline Cantclimbtom

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #23 on: Yesterday at 07:45:14 am »
Not always appropriate for a surface dig?  :shrug:
This is where expanding grout comes in. "Silent but deadly"
Edit: apart from the drilling
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Offline pwhole

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Re: Fabrication: Hanger with 10mm bolt hole
« Reply #24 on: Yesterday at 08:00:46 pm »
Bloody expensive though, at around £85 for 5kg. Though I don't know how far that would go on a set of large boulders - I'm guessing not that far.

https://www.dynacem.pl/uk/non-explosive-cracking-agent-dynacem-buy-online.html

 

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