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Proof loading bolts 27-Jul-2009 At 4:54:42 PM shmalec

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When I got my first job as an engineer, one of the old guys in the office had a sign over his desk.
"One test is more valuable than 1000 expert opinions."

We will always rely on a "design" approach to our climbing anchors. No one is going to test, certify and periodically retest every bolt in the country. We must rely on well designed equipment, good installation practices and a smattering of testing (a little of which trickles into the public domain).

Most of the time we are just guessing that X is safer than Y. Every now and again we get an opportunity to really learn something new from new information. This often occurs due to an accident. But sometimes we get access to some research such as Sedgman's Climbing Accidents in Australia. The point is that by performing some testing we get new information. We don't need to test everything. There is a large range of bolts, rock types, ages, corrosion, etc out there. I think it would be very enlightening to test 100 of them and see the results. Whatever the result, we will be better informed than before.

There are a couple of points to watch. Don't assume that the tested bolts are safe for a fall. They passed the test and that might give us confidence but that's all. Second, be prepared to replace the ones that pull out. Third, the load level is important. A proof test is usually applied to items manufactured in large quantities in order to assure a minimum level of quality. It does not translate across in any way to breaking strength. It should be low enough not to cause any damage but high enough to be meaningful. I wouldn't use an Aus Std. Find some meaningful data relevant to climbing falls. Finally, the testing equipment needs to be relevant. I've seen plenty of unrepresentative tests that are useless because something has been overlooked. An example in this case would be a pull out test on a single shaft glue in ring bolt where the ring is offset from the shaft. A pull out test on this would be damaging and not informative.

So Oldefella, sounds like a damn fine idea. Show us some more pics of your gismo. Is it calibrated? Does the shear pin rotate? Can you write down the details of each test to build up some useful info? How would you attach to hangerless bolts or carrots?