Can anyone lend us an underwater drill?

[cavemanmike]

Pm sent

 

[Leclused]

Rob - thanks; agreed. But the site in question is only 3 or 4 metres into the sump, so the battery could easily be left on land. Sam - thanks; yes, I'm sure you're right. But if the above was the situation, it'd only be the drill electronics we'd need to worry about. Worst case scenario is that it kills the drill (it's not going to cause a major fire in a sump). Maybe possible with a very old / sacrificial drill - or even a dirt cheap new one from Lidl / Aldi?

Here's a picture of the site. There is a thin airspace overhead (i.e. it's extremely shallow). What looks like the roof is merely a reflection; the real roof is very dark and is only about 20 mm above the water surface. You can see that the smaller slab to the right has suffered some abuse. We managed to jack the two apart to where they are now before both jammed. What we want to do is drill a line of 14 mm holes in the larger left hand slab, then use plugs & feathers to split it. Even chamfering just 100 mm off it would greatly help. We've been passing over this for a year with never more than 2 x 7 litre tanks on. I suspect that soon we'll need to get a lot bigger tanks through this restriction.

Does anyone have an old model of an SDS drill they never use (due to batteries knackered or superseded by a far newer / more efficient model) who might be willing to donate it to the cause? Maybe an old Bosch 24VRE, which has fairly unsophisticated electrics? I gave two away myself recently, as they were redundant (fool that I am!)

3-4M into the sump. Is this spot in a direct line with the surface? If so you could work with an extended drill bit and keep the drill above water.

If you can you could drill just one hole and put a straw in it ;-)

Extend method :

 

[Chocolate fireguard]

If taking only 100mm off the LH rock would improve things did you consider an SDS drill on hammer action alone?
At your shallow depth it might be possible to seal the whole thing inside a rubble bag if there is no rotating drill bit.

 

[Pitlamp]

Thanks for the suggestion Leclused - but the drilling angle is at 90 degrees to the passage trend, so not possible.

Thanks Chocolate fireguard; I suspect chiselling may not work; it's not normal limestone - it's basal conglomerate. So it doesn't behave like normal limestone.

I'm hopeful that we will soon have a sacrificial drill to have a go with (after receiving PMs from forum members).

Actually, I ought to say a general thank you to all the fellow cavers who have made suggestions on here, or sent PMs directly. It's amazing how helpful the caving community can be, when folk ask for help.

 

[oldfart]

Use an air drill. Skipton Hire Centre have some. Or, try Settle Coal.

 

[Pitlamp]

Use an air drill. Skipton Hire Centre have some. Or, try Settle Coal.

Thanks for the suggestion.

 

[Pitlamp]

Thanks - that's exactly what I was thinking; battery on the surface and a short cable feeding the actual drill.

Firstly, a big thank you to the various people who have been extremely helpful in relation to this project over the last several weeks. We now have a working system with a 24 V drill underwater connected via a (low resistance) cable to the battery on the surface. Being underwater does not kill the drill but we're struggling with the drill only spinning slowly. We initially thought the problem was the drag of the fan (moving water rather than air). But, after removing the fan, we pinpointed the issue as friction within the electric motor itself, when water-filled. Waterproofing this (so it's still running air-filled) is not really practicable.

We do have the loan of a pneumatic drill but there are some problems with this (not least of which is the possibility of hearing damage).

Our order for a proper Nemo SDS underwater cordless drill (see original post) appears to have fallen through; they don't seem to be being supplied by the UK importer any more and we've failed to source one overseas.

So I need to ask again; does anyone have a Nemo drill which they'd be willing to lend just for one afternoon? I'm wondering if any forum members are involved in the diving industry and may have one in the toolbox. If you think you may be able to help, please could you send a PM?

Thanks.

 

[cavemanmike]

Have you tried putting the drill in a sealed plastic bag with an air supply pump in from the surface

 

[Pitlamp]

Have you tried putting the drill in a sealed plastic bag with an air supply pump in from the surface

Thats an interesting idea . . . . will give it some thought.

 

[Frog2]

Not much use but on one dealers website - IMPORTANT : THIS TOOL (Nemo SDS rotary hammer) (V1) IS CURRENTLY BACK-ORDER WORLDWIDE. A NEW VERSION (V2) WILL BE ISSUE IN SUMMER 2022. RESERVE YOUR’S NOW AT V1 PRICE!

 

[Pitlamp]

Re cavemanmike's suggestion . . . might be awkward to get the buoyancy right.

Thanks Frog 2 - please could you PM me the link to that site?

 

[PeteHall]

Would a hydraulic core drill be an option? Obviously you’d need to be able to get a hydraulic power pack to the entrance! Might be easier to get hold of than an underwater cordless drill though…

I am looking into this option for Rickford.

You can pick up a 2nd hand hydraulic power pack for a few hundred pounds (that may or may not work!) or you can hire one that will definitely work for £100/week from Speedy.

The tricky bit is the underwater drill, which is about £3k to buy from here, or can be hired from an offshore firm in Aberdeen. If anyone else is interested in this as an option, let me know, as I'm talking to the suppliers already to see what might work.

 

[Pitlamp]

Thanks for the information Pete.

 

[Pitlamp]

Thanks for you PM Frog 2 - it may well be a game changer!

 

[Ad W]

I am looking into this option for Rickford.

You can pick up a 2nd hand hydraulic power pack for a few hundred pounds (that may or may not work!) or you can hire one that will definitely work for £100/week from Speedy.

The tricky bit is the underwater drill, which is about £3k to buy from here, or can be hired from an offshore firm in Aberdeen. If anyone else is interested in this as an option, let me know, as I'm talking to the suppliers already to see what might work.

My experience of hydraulic coring and borehole drilling equipment is that you get significant power losses through additional lengths of hydraulic hose as compared to compressed air. I've not used a a hydraulic hammer drill but you may need to be closer than you think to the power pack to maintain drill speed for the hammer action to work properly.

 

[Pitlamp]

My experience of hydraulic coring and borehole drilling equipment is that you get significant power losses through additional lengths of hydraulic hose as compared to compressed air. I've not used a a hydraulic hammer drill but you may need to be closer than you think to the power pack to maintain drill speed for the hammer action to work properly.

Thanks Ad W. Noted.

 

[Mark]

What about a 14mm core bit (no hammer action required)

Wet Diamond Core Drill Bit 14mm x 350 x 1/2in BSP (M) - DURO

The 14DPWC (Crown) is a professional wet diamond drill bit for high speed drilling with long life. Ideal for reinforced and non-reinforced concrete plus hard brick and blocks. Features: Crown Height: 8mm Bit Diameter: 14mm Bit Length: 320mm Dry/ Wet: Wet Ventilation: Requires Water Cooling...

rapidtoolsdirect.co.uk

and something like this (air consumption 3.25 litres p/s)

CP9791C Chicago Pneumatic 1/2" Pistol Grip Air Drill

CP9791C Chicago Pneumatic 1/2" Pistol Grip Air Drill - Industrial quality Jacob's keyless Chuck, Reversible, 800 rpm

www.powertoolsalesuk.com

Run off a 15ltr tank at 210bar = 3150 litres

gives you 16mins drilling time

All the above subject to available chuck sizes and me not really knowing what I am talking about

 

[georgenorth]

What about a 14mm core bit (no hammer action required)

Wet Diamond Core Drill Bit 14mm x 350 x 1/2in BSP (M) - DURO

The 14DPWC (Crown) is a professional wet diamond drill bit for high speed drilling with long life. Ideal for reinforced and non-reinforced concrete plus hard brick and blocks. Features: Crown Height: 8mm Bit Diameter: 14mm Bit Length: 320mm Dry/ Wet: Wet Ventilation: Requires Water Cooling...

rapidtoolsdirect.co.uk

and something like this (air consumption 3.25 litres p/s)

CP9791C Chicago Pneumatic 1/2" Pistol Grip Air Drill

CP9791C Chicago Pneumatic 1/2" Pistol Grip Air Drill - Industrial quality Jacob's keyless Chuck, Reversible, 800 rpm

www.powertoolsalesuk.com

Run off a 15ltr tank at 210bar = 3150 litres

gives you 16mins drilling time

All the above subject to available chuck sizes and me not really knowing what I am talking about

I don’t think that would be anywhere near powerful enough to spin a core bit unfortunately. Core drills have pretty powerful motors for high revs/high torque.

You also need a threaded chuck for core drilling - a jawed chuck would just slip I expect.

 

[Pitlamp]

Thanks Mark. (It's amazing how helpful folk are on here.)

Thanks George.

 

[Mark]

I assume you have tried jacking them up and digging out underneath them