Posted: Mon Apr 02, 2007 10:05 am
How does one become a "whipmaster"? 
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Posted: Mon Apr 02, 2007 10:13 am
Ask Wes
Posted: Mon Apr 02, 2007 10:20 am
Nice work! You sure love to experiment.
Sooo.....using 1/4" 304 ss, cold working it to shape? I would think after a few falls the rod would start flexing/ bending. After hundreds of falls at slightly different angles wouldn't this cause stress fractures from work hardening. My concern would be at the sharp bend.
Sooo.....using 1/4" 304 ss, cold working it to shape? I would think after a few falls the rod would start flexing/ bending. After hundreds of falls at slightly different angles wouldn't this cause stress fractures from work hardening. My concern would be at the sharp bend.
Posted: Mon Apr 02, 2007 10:21 am
Speak for yourself, child. I'm pretty long in tooth!caribe wrote:Rick:
...My opinion is that the assembly will probably age to uselessness long after you and I have left the planet.
Yes. Hilti has published some. I'll try to dig them up. Of course, no hanger will last forever.caribe wrote:...Are there studies on the aging of this epoxy adhesive crossed with its performance over time? Arthur
Rick
Posted: Mon Apr 02, 2007 10:51 am
An epoxy anchor in a roof might not be the best scenario. Read some of the info from the Bid Dig ceiling panels. Because of this failure, engineers will never use epoxy anchors to hold up anything in a pullout only loading scenario. Shear loading is OK but not pullout. Epoxy performance is too sensitive to minor imperfections during installation. A small mistake can result in a huge loss of strength.
http://www.boston.com/news/traffic/bigd ... re/?page=1
http://www.mass.gov/ig/publ/catboltr.pdf
http://www.boston.com/news/traffic/bigd ... re/?page=1
http://www.mass.gov/ig/publ/catboltr.pdf
Posted: Mon Apr 02, 2007 12:33 pm
Ask Gaar to be a whipmaster! After that 20+ whipper he took on that cam, I bet he could give you some serious results. 
Posted: Mon Apr 02, 2007 12:37 pm
Now I see why you're on his hit list, sloop.
Posted: Mon Apr 02, 2007 1:53 pm
From the Mass. Inspector General's report linked above:
That's kinda scary in a construction environment - but pretty damn scary in a climbing environment. I suspect that most route developers are a bit more careful than the guys up on scaffolding slamming thousands of bolts in under a deadline!According to the bolt manufacturer's information, industry standards, and vendors contacted by this Office, when anchor bolts are installed properly the failure rate is minimal (usually around one percent).
Posted: Mon Apr 02, 2007 2:06 pm
I'd guess that if the peak force on the harnes was around 800 lbs., that the force on the 'bolt' would be roughly 1,500 lbs. - so enough to crack the rock and cause the 6mm 'wire bolt' to yield/deform a bit. Would you be able to run a similar test with the load cell acting like the quickdraw clipped between the rope and the 'bolt'?weber wrote:I'll try to located the tests that were done recently with a load cell on a falling climber to determine the maximum safe load he can take before bodily injuries start occuring. I think it was about 800 pounds on the harness. I would guess that repeated big whips in this range could distort this bolt over time, but how much? We can easily test this, once we determine the max. falling force.
Our load cell can be attached to a falling climber to see what a typical big whip of say 30 feet would generate, but of course we don't want to test to the point of injury.
We have some more prototypes on the way here that are made from 8 mm s.s. rod instead of the 6 mm of the ones in my post. Problem is, they cost quite a bit more and require a 15mm-dia. hole with a lot more epoxy. Their strength will be way off the scale on the high side.
It sounds like the 'dream' solution would be one of these 'bolts' made with 8mm rod at the 'eye' that tapers down to 6mm where the twisting occurs. I don't have a clue about how such a thing could be manufactured, but I'd guess that it would be even more expensive than the straight 8mm version!
We are wrapping up construction of a BIG new veterinary clinic and are about to order a lot of equipment - surgical tables, sinks, cages, etc. - all stainless steel. We discussed pre-ordering a lot of this stuff with the owner last year, and he decided to put it off.... gulp!The Chinese insatiable demand for steel is driving the price of steel and stainless steel through the roof. All fasteners -- mechanical, glue-in, etc. are going up in price.
Rick
Posted: Mon Apr 02, 2007 4:15 pm
weber wrote:Actually, we are working out less messy ways to install these critters. The best way for keeping overhanging bolts and the epoxy in place until it sets up is to use a brass bushing that I machine specifically for this operation. It jams the bolt into the hole and retains the epoxy from running out. Some developers put a piece of gorilla tape (duct tape on steroids) over the hole and put a tiny slit for the bolt and glue to be inserted. This holds the glue in place. And a piece of tape over the eye of the bolt holds the bolt from slipping out.
Rick
that sounds cool too, but not exactly what I was wondering.! will said brass bushing allow a developer on rappell to clip into the freshly set glue-in, thereby allowing easier access to the next placement?
anyway, good work rick!