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I am most interested in setting up a top rope anchor on 2 bolts side by side. I feel like in this case you almost have to be more careful using bolts for a top rope than sport climbing because in sport climbing you are clipping a bunch of bolts all the way to the top, so if one fails, there is another one in different rock that will probably save you to-where-as if one of two bolts for a top rope are in bad rock, both bolts are probably in bad rock. Specifically I am asking:

How to inspect a climbing bolt?

Are there any non-obvious things to look for when inspecting a climbing bolt?

If a bolt is placed very close to the edge of a corner of rock, what proximity is considered safe? (I am thinking of some climbs where the bolts are literally only a foot from the top of the cliff - could the combination of the bolts shear off a piece of the rock ?)

Also, do bolts ever fail catastrophically? i.e. just blow out of rock, or do they tend to fail over time so you can see it coming and avoid those bolts ?

Thank you very much for your input.

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This may speak to some of your concerns: American Safe Climbing Association

The American Safe Climbing Association publishes guidelines for safe bolting. Their stuff usually targets the people who are actually doing the bolting, but can be worth reading for general purposes. They have articles on how to tell which bolts are good and which are bad. And the have a lot of other interesting safely stuff

The list below is all fairly subjective, and you should still read the ASCA's website, but here's what I look for -

  • if you're at a popular climbing area on an established climb, the rock for the bolts is probably fine.
  • look for "choss" around the bolts - is the bolt attached to any rock that looks loose or broken, or sounds "hollow" when you thump it with your palm? A foot of solid rock on all sides of a bolt would normally seem totally solid.
  • Look at the type of rock? Is it granite? Is it a bomber variety of sandstone? Or does the route generally have a lot of broken, hollow-sounding, or rattling holds that make noise as you climb on them (a bad sign), or does it feel like a giant, solid mass?
  • is the bolt itself showing an unusual amount of rust
  • double check that the bolt itself is reasonably tight. It doesn't have to be totally ratcheted down, but it should be right enough to more or less hold the hanger in place, and have enough threads sticking out the end that it couldn't unscrew while climbing.
  • You can build a double sliding-X (with limiter knots) if you want to make sure you're distributing the load between both bolts. Use a pair of double-length slings. Put lockers into each bolt, and a pair of lockers (opposite and opposed) at the master point.

Bolts will sometimes fail, but not that often. The only time I've heard of it was on a new route when the route bolter wasn't finished with the route, but didn't adequately communicate it. He had a known-bad bolt on a route, and it blew when someone took a lead fall on it: Bolt Failure at New River Gorge

If you doubt the bolts, you could certainly rig an anchor (or a backup) off trees or boulders near the top of the route (if one is available), or just not do the climb. Trust your gut on this stuff - I think that bolts are generally safe, but don't know your area.

Good luck, David

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Besides the good ideas in this answer, you can also get information about the bolts in a particular area by reading guidebooks or looking at online info from mountainproject or summitpost. There are also certain sizes and types of bolts that are suspect, and you can get info about these from John Long's book on climbing anchors. – Ben Crowell Apr 5 at 14:10

In addition to what David mentioned, their are area specific concerns and, specific ways to check bolts in those areas. Most of the time the generic advice will be useful, but please make sure you speak with climbers familiar with the area you're going to understand about possible bolting problem. Also climbing guides usually contain this information, but not always.

A perfect example of this is Thailand, where bolts corrode badly even when they look perfectly fine outside. To make matters worse you can find two bolts next to each other, a matte Titanium bolt and a shiny steel bolt. First instinct is to clip the shiny bolt, while Titanium bolts are the new ones that won't corrode. Also the type of glue used is important is a way to identify better bolts. You might not go to Thailand, but I mention this just to make it clear that it's important to go beyond the generic advice.

For more information about Thailand's bolting problems go to

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Good point. Talk with other climbers and / or climbing groups in your area. – DavidR Sep 10 '12 at 14:57
I forgot that there are places where otherwise good bolts can go bad. Apparently limestone + salt water == chlorine gas == steel bolts corrode quite quickly. – DavidR Sep 10 '12 at 15:49
Yes, even marine quality steel that won't corrode in other environments can't be trusted. It's scary to even think about it, but the guys in Thailand are doing a great job to address this issue. Same at the Cayman islands. – Miguel Madero Sep 11 '12 at 4:07
@DavidR and Miguel Madero: This forum is awesome mann! Thanks alot guys for the info and tips. – WedaPashi Jul 16 '13 at 5:37

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