"Gregarson? had his locks tested and the results were published."
Gregerson locks were tested in the 1990 study. The mean breaking strength was 339 pounds."the cable would cut through the thin metal of the lock when the captured animal attempts to free itself. Is there any application here to s-hook BAD systems"
I don't see how. It is an entirely different system."Hal I would love for you to attempt to tear one of these locks out.."
Heck, I'll bet you would. I'll bet you'd love to have me mow your lawn too.
You seem to be as interested in this as anyone, in fact more so. Again I invite you or anyone else to undertake some of this on your own.
Frankly, I'm not going to do anymore of this until I get a different system set up. Something on the order of what Ric has. But that doesn't mean the tests I have used are invalid, the testing system is just a little slow.
But before this thread ends, maybe I should delineate a simple testing system, and how anybody can do this test at home.
For starters, you'll need a some sort of a scale, a bathroom scale will do. You'll also need a comealong to pick up the weights, and you'll obviously need a place to hang the comealong. I hang mine from a beam in the ceiling.
My original set up employed concrete blocks and a couple pieces of pipe to hold them. Set the blocks up endways and run a piece of pipe through them. I used two rows of block with two pipes. Then I used a piece of chain to capture the ends of the pipes sticking out of the blocks. For the pulling mandrel, I used a piece of pipe about 12 inches long. (If you want to replicate the 1990 DWR tests, get a piece of 2.5" inside diameter pipe, this will be about 2.9" outside diameter.) I would capture one end of the pipes sticking out of the blocks, run the chain through the hollow of the pulling pipe, and then capture the other end of the pipes sticking out of the blocks..
You need to weigh everything below the comealong, the blocks, the pipes, the chains, the pull pipe, -- everything. Do this incrementally and add up your total. It is best to start with a weight below the expected breaking point of the BAD. Unhook the chain, thread a snare on the pull pipe, then rehook the chain.
Working the handle of the comealong slowly, pick up the load. (Don't jerk or bounce the load.) All you need to do is clear the load from the floor a fraction of an inch. If the BAD doesn't let go. Set the load back down carefully.
Next you will need some items of known weight to add to the load. I used bricks there's so many different kinds that I can't give you an approximate weight for one brick, but to speed up the process of doing this test, add weight in 10 pound increments. If your bricks weigh approximately 5 pounds, add them to the load two at a time.
Eventually, the BAD will fail. At this point you can weigh the total additional weight you have added to the pile and come up with a total weight number for that trail. Don't rely on just one trial. There can be variances in these things. You should do at least ten trials and take an average.
Note, that you should always use a new lock, and new BAD for each trail. The hole on a lock tends to distort once it has been subject to a BAD failure. And BADs should never be considered to be re-usable.BE CAREFUL! BE SAFE!
These BADs can fail violently, with pieces being propelled away from the snare with some force. Please wear some form of eye protection.
Also be mindful that a load this heavy could very quickly smash your toes. I circumvent this by standing on a ladder to work the comealong. I stand on the first step of the ladder, and my feet are thusly off the floor.