Tech skills: spot a bad bolt

Posted by Alex Messenger on 14/12/2011
Can you spot a bad bolt? Photo: Alex Messenger.
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You're cranking it out, going for the onsight. But what's in the rock, stopping you from hitting the deck? The UK has an assortment of bolts; from old to new, hand-made to manufactured. Can you tell the difference?

It looks fine, just clip it…
Bolts used in climbing come in two main types, mechanical or resin. Both have a vast variety of different styles, sizes and, ultimately, strength. What is worth noting is that bolting happens on a voluntary basis in the UK. The first ascentionist usually buys and places the bolts, and these are usually what was available at the time – some were made in a shed, some bought from a hardware store, others even from a bolt manufacturer.

Mechanical bolts
Mechanical bolts work by expanding or compressing a collar that grips and presses against the wall of the bolt hole; there is no resin (glue) involved. Generally mechanical bolts are only suitable for medium to hard rock, and any movement in the hole should be considered suspect. There are many types, some safer than others, so it's good to be familiar with what they look like so you can make safe choices before you end up passing one at increasing speed.

If you see a thread looking at you with a nut holding a plate hanger, then it's the most common expansion bolt. Found in either 10mm or 12mm bar diameter, these are a good bolt to clip to. If you see a bolt head with no thread then, depending on the diameter, this will either be a caving 'spit' (13mm spanner size) or a sleeve bolt. The caving spit is the scary one as it enters the rock by a measly 15mm; sleeve bolts are OK. Compression bolts look like a drawing pin and are not as strong as you would wish for. Naildrives or Petzl Long Life bolts are one of the strongest mechanical (and most corrosion resistant) bolts you will find – but you won't find many due to their hefty price.

Resin bolts
Resin bolts are made out of a bent 8 or 10mm stainless steel bar, either in a welded 'P' shape or a 'U' shape (aka a staple). They are far superior to any mechanical bolt but the two holes compromise the strength of the rock so placements in some rock types are not as strong as in others. Resin does not like sticking to stainless steel either so the best ones are those that have the greatest mechanical adhesion for the resin to key into. Caution should be taken when clipping to a resin bolt that moves; those that are counter sunk into the rock are less likely to move.

Resin and corrosion
All metals will corrode, even stainless steel, and this will happen especially fast if a mix of metals are used or if they are next to the sea. Stainless steel is the material of choice but it's important to check that both the bolt and the hanger are made out of the same material. If you see a bolt that looks rusty and a hanger that is bright and shiny, go and do a different route! The number of bolts I've sheared off with a spanner when replacing them is scary. Aluminum hangers and steel bolts will also place you next to your belayer, in need of medical care.

Corrosion needs a place to start. A bolt that is polished smooth and has no corners. A highly polished 316-grade stainless steel with no welds is the best for sea cliffs, so that's what we've used in Cumbria. Remember that any bolt is only as good as the rock it is placed in. Use your own judgment and be wary of bolts placed in loose or soft rock, near cracks or close to edges.

Sustainable bolting
Our cliffs are a finite resource and it is up to us to preserve them into the future. The rusting remnants of previous bolting eras are unsightly. It is possible to remove a mechanical bolt, but the process takes four times longer than creating a new placement. This is expensive and unrealistic for volunteers to do unless it is a vital position to make that clip during a move. Some resin anchors can be removed with the right kit and are longer- lasting. So, although they take longer to place, use up more battery and cost a little more than mechanical bolts, they are well worth the investment.

Dan Robinson lives in Cumbria and is head of Real Adventure, running adventure and education bespoke residential courses, technical skills training and SPA / ML courses. He holds the MIC and is Chair of the Cumbria Bolt Fund.

Expert Q&A

 

Q. Who is responsible for the bolts at a crag?
A.
In general, nobody. As a climber, it is your own responsibility to check that any bolts or lower offs that you rely on are secure. Never assume that it's safe just because it's a sport route.

Q. Can I tell if a route is safe before leaving the ground?
A.
No, but you can build up a picture. The guidebook may indicate when the route was equipped and with what. Some areas have Wikis with info on specific routes. You may be able to get a good look at the type and condition of some of the bolts, and their spacing, before setting off.

Q. What if I reach dubious-looking bolts when leading?
A.
With luck you'll have been scoping things out from below and aren't too committed. Down climb to the last good bolt to retreat. If you don't want to leave a good quickdraw behind, carry a maillon or cheap 'bail biner' and swap over to that before lowering off.

Q. What if the lower-off is worn or damaged?
A.
This can be a real problem in popular areas. Always top rope on your own quickdraws or krabs, with the last person cleaning the route. If the lower-off is badly worn, make a judgment call. If it is worn more than a third through, don't rely on the damaged parts. This may mean having to retreat using the last bolt. Don't assume all parts of the lower-off are strong enough to clip into: there are some Heath Robinson affairs around which could give you a nasty surprise.

 



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1) Anonymous User
30/07/2012
Useful article but it would be even better with a few good pictures to illustrate.
2) Anonymous User
12/09/2012
This not anonymous; my email is mb4d@madasafish.com Some years ago I had to provide a stainless steel armoured cable buried in coastal sand, ie a marine environment. One of the risks of this environment is stress-cracking of ss. Grade 316 is indeed a marine grade but I would check its use in the context of bolts. In the case of the cable I specified grade 304L, L signifying Low Carbon. I am not a metallurgist so cannot comment with that degree of expertise, and the grade of ss that I specified did not have the same mechanical stress that a bolt would experience. I would contact the Stainless Steel Association for advice. Malcolm Brentford
3) Anonymous User
10/11/2017
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