UKC

Sustainable Rebolting

New Topic
Please Register as a New User in order to reply to this topic.
 Cheese Monkey 01 Jul 2024

Inspired by a recent HowNot2 vid I have purchased some core bits and trialled it today.

If you aren't aware most expansion bolts used in the UK are extremely difficult to remove. The current best and realistic practice I am aware of to rebolt either involve cutting the stud or hoping the hole is deep enough to knock it in flush. Masking with resin. Drilling new hole and new bolt.

I say there is now a better way that we should be doing. I used a 13mm core bit today with a 10mm ID and with water feed to successfully remove 2x 10mm expansion bolts. The resulting 13mm holes then suit 6mm glue in twisties from Bolt Products perfectly which should last far longer than any expansion bolt with the correct resin. The removal process was very straightforward.

I'm posting because I think its great and a real step forward in caring for our crags and I hope more people try it out.

 dunnyg 01 Jul 2024
In reply to Cheese Monkey:

Caving has had similar thoughts and come up with this in the dales.

https://cncc.org.uk/equipment/ic-anchor/

 kristian Global Crag Moderator 02 Jul 2024
In reply to Cheese Monkey:

I'd be interested to know what kind of rock you tried this with?

Soft vertical rock is obviously going to be a breeze compared to overhanging hard rock.

This is all very good if the rock and position allow but there are also so many instances where the original location of the bolt can be improved upon. 

It may also be worth considering widening the hole some more to accommodate the larger and more commonly used BP twist bolt especially in soft rock. 

I've removed a fair few expansion/wedge bolts over the years and as you know it is frustrating when the holes weren't over drilled for knocking flush. I have found that if a bolt has bottomed out or you are suspicious the others will be the same it is worth if possible to tighten the bolt as much as possible. This will draw it back out from the rock before cutting it with the angle grinder. Being careful not to score the rock with the disk. Hopefully there will be enough movement then for the stub to be whacked flush.

 kristian Global Crag Moderator 02 Jul 2024
In reply to Cheese Monkey:

It's so much easier to re bolt a route with the assistance of the old bolt when the route is steep or wandering especially when placing fiddly glue in bolts.

 JLS 02 Jul 2024
In reply to kristian:

>"and as you know it is frustrating when the holes weren't over drilled for knocking flush"

A cordless angle grinder kinda solved that problem for me.

Post edited at 08:48
2
 JLS 02 Jul 2024
In reply to Cheese Monkey:

It looks like a good method in the right circumstances.

That said, it's going to be pretty time (and battery) consuming to replace a route. The reality is crag stewards often just don't have the time and resources to do the best job possible and have to compromise down from ideal.

1
 sheppy 02 Jul 2024
In reply to Cheese Monkey:

Decent 316L expansion bolts properly placed should be lasting for a long long time. I assume you are referring to old non stainless items? 

As to cutting off the old studs, if they are 10mm they generally snap off very easily with a few concentrated hammer blows in opposite directions avoiding risk of angle grinder disc/rock contact.  Conveniently they sometimes break off just under the surface of the rock.

Might be worth having one of those core bits in the tool box though, are they expensive?              Jim Titt does recommend a 12mm hole for his 6mm twisted leg bolts but that does make them harder to fit.

OP Cheese Monkey 02 Jul 2024
In reply to Cheese Monkey:

Thanks for the replies. If there is a reliable method of removing old bolts, we absolutely should be striving to do this regardless of how long it takes, not leaving them in the rock and creating additional holes over and over again. More effort is needed to engage more people to do this stuff (BMC office led would be a start), then all of the convenience/time concerns go away. 

2
 JLS 02 Jul 2024
In reply to Cheese Monkey:

>"If there is a reliable method of removing old bolts, we absolutely should be striving to do this regardless of how long it takes, not leaving them in the rock and creating additional holes over and over again."

I suspect you may have trouble convincing many bolters do this for the second generation bolts, where you'd want to hang off the first generation bolts to place the second.  You may have more luck convincing people that any third generation bolts should go back to the first generation positions using this method. Hopefully, going forward any second generation bolts will now be glue-ins and a third generation of bolts will rarely be required.

 spenser 02 Jul 2024
In reply to Cheese Monkey:

Pop me an email with ideas if you would like and we can have a discussion, following that I can ask Dan to put something on the agenda for the next tech committee meeting (any follow on work would be volunteer led as Dan's focus is required on other bits of the BMC at present).

Guidance would likely be provided as part of the BMC bolt guidance document for installers:

https://www.thebmc.co.uk/bolts-advice-guides

I am pretty sure that Galpinos (of this parish) mentioned something about a UIAA bolting guide at our last meeting but my tablet is not playing ball with teams at the moment ( probably to do with being in France) so I can't check the plenary report from UIAA Safecom at the moment to confirm.

1
OP Cheese Monkey 02 Jul 2024
In reply to spenser:

Will do, however my point was more of a general one in engaging people to volunteer their time to do look after our crags, which I have been trying hard to do locally, but more pushing from above would be beneficial

I would be keen to give a brief report at the next tech committee if there is appetite for it. 

 Rick Graham 02 Jul 2024
In reply to spenser:

Had a quick glance again at the bmc guide but its mainly for installing bolts not removing them.

The original Lakes bolt fund team had a diy  extractor which rarely failed in its mission, now sadly misplaced. The team also had lots of other options for removal, some mentioned above. 

If hammering, often better to cold chisel a nick in the bolt both sides first, helps the crack propagation process. If you cannot swing a hammer accurately, a flat ended bar will improve aim and damage the rock less. As others have said , it only takes a few blows up and down on a bolt before it snaps.

Buying a core drill, follow the instructions with a quality one. I bought a £30 silverline one, did not  manage a single trial hole in soft slate .

If  levering out , often the hardest issue is getting a fulcrum point close enough to the bolt to get the required mechanical advantage ratio. Also devising a method that works hanging on a rope rather than just at ground level.

There is also some US u tubes of methods to get out through bolts using a power drill and drawer.

Will DM some sketches of bolt drawers we have used.

 spenser 02 Jul 2024
In reply to Cheese Monkey:

I am fully in support of the idea of encouraging more people to learn how to replace anchors etc. 

As above drop me a message and I'll see if there is any interest from Dan and the committee.

 Pete O'Donovan 02 Jul 2024
In reply to kristian:

Hi Kristian,

With regard to removing old, bottomed-out bolts, have you tried using a longer/heavier spanner setup (diy models are relatively easy to make)? 
With the extra torque on the nut, it not only pulls the bolt out further than a 'normal' spanner, but usually snaps it off (no need for an angle grinder) at a much shorter length for it to be hammered back into the rock and concealed.

Pete.

Post edited at 18:41
 kristian Global Crag Moderator 02 Jul 2024
In reply to Pete O'Donovan:

That's a very good idea Pete I'll give it a go.To be honest the majority of the old bolts I remove are so rusted that the whole unit turns or the nut rounds off before I'm able to apply that much torque. I'll usually end up angle grinding diagonally at the 90° of the nut and bolt.

Post edited at 18:57
 kristian Global Crag Moderator 02 Jul 2024
In reply to JLS:

But if the bolt is already grounded out you can't knock it flush or under if it snaps or is cut slightly proud so pre extraction in this case is desirable so it can sink back in.

 JLS 02 Jul 2024
In reply to kristian:

>”if the bolt is already grounded out”

True, but there’s generally some over drilling plus what was pulled out as the wedge engages.

 spidermonkey09 02 Jul 2024
In reply to Cheese Monkey:

I always take old bolts out if they are easy to do but there's no denying it massively increases the scale of the job. You end up hanging on them while you place the new glue ins and you can't load the glue ins for a few days after placing. So in reality, however nice it sounds to say remove them however long it takes, you're asking people to basically double the length of the job, because they'll need to come back another day with the grinder and take them all out. In that context I think the maximum you can realistically ask volunteers to do is take the hangers off and try hammering them flush. That's before you even get onto the issues Kristian raised about bolting harder routes which are on steeper rock and the associated difficulties involved. Too often in bolting we are letting perfect be the enemy of good. If someone is willing to give up their time and volunteer to rebolt something it's taking the mickey to then demand they spend double the time. Not saying you're doing that, just a call for realism. 

Post edited at 20:40
11
 Jonathan Emett 06 Jul 2024
In reply to JLS:

I'm too clumsy with a grinder, I always seem to end up scoring the rock somehow.

I've started using my Dremel for this sometimes. Because it spins in the same plane as the rock you can cut through the bolt cleanly. it works well, if a bit slowly.

 Gary Gibson 06 Jul 2024
In reply to JLS:I’ve spent almost a lifetime regearing routes and the best is to remove the hanger and tap the old bolt into the rock and cover with glue then replace with a stainless 316 glue in and I doubt anyone has ever done more than me


New Topic
Please Register as a New User in order to reply to this topic.
Loading Notifications...