UKC

Hi all,

We have a school wall that I'm in charge of. A number of the bolts are no longer useable for holds because, somehow, we've knackered them putting in and taking out holds. Quite a few of those are inaccessible from the back because of various beams, etc. Is there a standard procedure for replacing bolts? I guess it will involve removing the panels, etc? It's an entre-prises wall so am wondering about ringing them to ask if they'd be able to do it.

Thanks in advance for any advice.

Jim

Assuming we're talking about M10 T-nuts in standard 19mm thick plywood panels; these work. Punch out the existing dead T-nut. Drill the hole to the correct diameter and screw in. Take advice and practice first on some gash wood.

http://www.theinsertcompany.com/steel_hex_drive_inserts_for_wood_unheaded.p...

For your info (particularly if you're looking for replacements), the things you're talking about here are "T-nuts" not "bolts".

Yes, getting at the inaccessible ones would most likely involve removing/replacing the panel.  Besides the original supplier there are several different companies you could probably pay to sort it out for you, somebody might be along to recommend one or more of them in a bit.

Some of the indoor walls with plywood panels (eg: the Climbing Works) have abandoned t-nuts now and simply screw their holds onto plain plywood.

Thanks - T nuts! Those Hex Drive inserts look interesting - my fear would be whether or not I could punch out the existing T-nut where it's straight into a timber?

I will admit I haven't used this product but I'd be VERY wary of using a self threading insert in a safety critical situation. Especially one involving minors, a duty of care and plywood probably already weakened by pinning screws!

They would most certainly not be used in any of the walls I'm responsible for maintaining!

cover them with a small  volume ...

Just sent you an email, Jim. 
 

What’s the worst that could happen. A hold might spin.

A large hold might come off the wall, complete with bolt and insert, and drop on someone's head.

I would be worried about the total strength of the insert compared to a T nut in ply - it's probably strong enough to work, but not a big enough safety factor to keep me happy. I would also be worried about the bolt securing the hold to the insert being done up tight enough that the insert unscrews from the ply when someone's pulling on the hold (unlike a normal case where the hold can spin but is very unlikely to unscrew a the bolt). Better if the insert is driven a couple of mm below the surface of the ply I guess.

Not saying I wouldn't use them, but I would want to see some examples of busy walls where they have been used successfully first, or see them recommended by a wall-building company.

So when was the last time you saw a hold come off at the wall.

Only once, at least 5 years ago. Never at all on a wall with T nuts.

A couple of months back I pulled the t-nut straight through the ply-board on the first move of a boulder problem.

So you have seen one hold off come possibly over 5 years ago. How many times have you seen poor belaying in that time.

Whats the greater risk the wall or human error. 
Edit clearly T nuts also fail according to Josh.

At the end of the day climbing is a risk activity, that’s why people do it.

The point is that I spend the vast majority of my time at a wall where the holds are secured by T nuts through ply (or in some cases, sufficient screws), and the holds don't fall off. I used to use a very old and shonky wall using a different approach, and saw 1 failure. But neither of these say anything at all about the risk of failure when using screw-in inserts. 

With a climbing wall other people will use (especially kids) I would want the tried and tested options. That means T nuts, or finding an example where these things have been used successfully, and asking them for the details (I think maybe andyr can provide that, in which case fine, but I took exception your making light of the potential consequences of fucking this up)

Don't be daft. 8 metres up, a hold comes off and lands on the belayer's head. Even with a helmet that could be nasty. Not least for the poor sod on the other end!

Oh, and in answer to one of your other questions, I personally know of at least 8 holds pulling of a wall. 

In answer to another, not many, relatively, come off because EVERYONE uses tee  nuts with a plate on the back not some self tappy jobby.

And thirdly, yes. It's a sport that carries a risk but you do all you reasonably can to mitigate that risk. Otherwise, why bother with wall inspections? Why check ropes and harnesses? Hell, why even bother with ropes and harnesses. I mean, it's only a school wall. What could possibly go wrong...

So you know of 8 holds that have pulled through I.e ripped the T nut out.

Yes but unless you have evidence than an insert fitted into a used, punched out hole is as safe as a normal method, you are using a broadly known risk level to justify a totally unknown risk.

Which is a foolish thing to do. Nonsensical in fact. It’s tantamount to saying “climbing is dangerous. So is electricity - here’s a potentially live wire (I don’t really know what voltage though) how about you touch it?”

There’s no way in hell I would trust an insert - especially when it’s loaded at funny angles.  I expect the insurers would be more than a bit perturbed at hardware being used outside of the spec of both its manufacture and the wall’s manufacturer.

I’m going out on a limb here and nuts with flanges to the rear are used over inserts for the bloody obvious reasons of (a) further spreading the force away from the timber weakened by drilling and (b) not being able to pull through the hole.  Sure - they can still fail but with I suspect a much larger safety margin than inserts.

I didn't say that. I know of one coming straight through. A couple overused threads being worn down. Some where the tee nut sheared from the backplate and at least one where there wasn't enough thread on the bolt through the hold.

Y'know. I swear some people come on here looking for an argument.

I work in this industry. I've replaced hundreds, probably thousands, of tee nuts for various reasons. I would NEVER replace them with something that doesn't have a backing plate.

Would you like a medal for your services to T nuts.

The risks adults choose to take vs the risks permitted in a school setting with someone else's children.....

Its amazing they are still allowed to climb in the current risk averse climate.  It's not worth it.  

Or in other words, the worst thing that could happen, schools are banned from having climbing walls following a knee jerk reaction to an incident.  

#Gainz

Do you think it's ok to secure holds just by self-tapped screws, as is common nowadays in plenty of walls?

https://gripped.com/indoor-climbing/a-volume-broke-off-on-jernej-kruder-at-...

A volume to be fair. But only last week. Well a volume on a volume... 

First option if t-nuts are in place still would be to re-tap them.

If its an EP wall the t-nuts will be screwed in place.

If you were looking to get a company in to remove panels and replace them i i would weigh up the cost of this with the option of buying volumes with t-nuts in or screw on holds.

https://www.holdz.co.uk/collections/volumes 

https://coreclimbing.co.uk/buy-holds/shop-by-type/jugs/font-screw-on-mini-j... 

The Dynafix threaded tnuts could be added additionally by drilling more holes and adding them but from experience not the longest lasting.

Failing all that i have a company that does bits like this. (Shameless plug) can always look to sort it out for you.😉

Try cleaning up the threads with a tap

https://www.eurocarparts.com/p/am-tech-6pc-tap-wrench-set-553777410?type=sh...

an example not a recommendation, other brands /suppliers are available.

Don't let folk lose with power tools till they know what they're doing.

And remember the wall needs to comply with appropriate EN standards so don't mess about with it unless you know what you're doing. Courts don't take kindly to the "a big boy on the Internet told me to do it" defence. 

Buy a tap and die set, good for sorting out threaded t nuts and also sorting any bolts where the threads might have been damaged. Make sure you get one sized for m10.

https://www.screwfix.com/p/tap-die-set-10-pieces/3783V?tc=QT7&ds_kid=92...

Buy a tap and die set, good for sorting out threaded t nuts and also sorting any bolts where the threads might have been damaged. Make sure you get one sized for m10. If the t nuts have fallen out of the back of the panels remove the panel if possible and replace.

https://www.screwfix.com/p/tap-die-set-10-pieces/3783V?tc=QT7&ds_kid=92...

Yes. But with qualifications.

If the hold is designed to be attached by screws then yes. These are either generally smaller holds or large holds with multiple screw holes. Small holds, much less chance of hurting someone if it comes off. Large holds then, obviously, reduces the risk of one failing. And ALWAYS there'll be two screws*.

Replacing one tee nut with one screwed thread is, in my opinion, not safe even if edge pinned.

*Just for accuracy, I have seen a few single screwed holds. Xcult rings a bell. But they were tiny. Not much bigger than the screw. Even the old EP Supertweeks had two screws... 

It's possible to re tap the T-nuts with a standard M10 tap and die set. Back in my youth we re did the whole main wall at the ice factor as loads of T-nuts had got knackered over the years from cross threading etc.

It's better to replace if they are really knackered but that would likely involve removing panels etc and is a much bigger job.

Toulouse Olympic qualifiers?

In person, last year.

CB

Call Entreprises UK - they will sort it for you...

Think through the HSE aspects, compare:

Accident happens or inspection occurs:

-> investigation finds DIY "fix" involving non certified threaded inserts that are not approved or tested "fit for purpose" installed by unqualified amateur seeking advice on a public forum (which clearly points out the problems)

or

-> investigation finds a relevant certified and insured professional serviced the wall

Which end of these two options would you prefer to be on the end of?

As there is a lot of 'opinion' being posted here I thought I'd offer some facts. The inserts industry is well established (a T-nut is an insert) and there is a wealth of stats and data available to make informed choice.

For testing purposes, round flanged M10 T-nuts were secured in EN 636-2G 18mm ply.  These were rotated to destruction. The holes were then enlarged to 15mm and M10 hex head inserts installed. Using a Hydrajaw 2000 pull tester they were loaded to 12kN and left for 30 minutes. There was no creep on the scale which would have indicated crushing under the threads. They were then loaded to 20kN (maximum on that particular machine) again with no creep. The test was repeated daily 47 times (it was supposed to be 50 but we got bored) to represent repeated route setting. No failures or loss of performance.

Cool.  But interesting as they are, your facts are no use to anyone unless you cite the source. 

Also the inserts that people are expressing doubts about are the ones you posted a link to above (these: http://www.theinsertcompany.com/steel_hex_drive_inserts_for_wood_unheaded.p... ), which are not t-nuts, so your facts are irrelevant to those.

That's what web search engines are for.

You might take a moment to re-read the paragraph.

It is in a school.

I googled it doesn't really cut it for health and safety.  

To find the source of the 'facts' you're stating?  Seriously - you're happy to share the info, but you can't be arsed to say where you're getting it from?  Righto.

Oh yes, my mistake sorry.