Hi Tom. I've been reading through this post a bit and was a bit confused by some of your posts so I corrected them below to what you probably meant to say:
"Merlin is another large cam for those crazies that like to climb off-width. It has some really innovative ideas and I tip my hat to it's creator for his obvious engineering prowess. I think both VG and Merlin have their advantages and disadvantages but truth be told both cams are great and only add to the wonder of climbing. I know Erick and I don't do this for profit and only do it out of true love of the sport and to give something back to the climbing community. So in that spirit I say again good work brother! I am impressed"
With all this conversation about the safety of self-made cams, I totally forgot to mention this story I heard in 1983:
Some guys from Australia made their own cams, but they used the wrong spiral profile. Instead of an exponential/logarithmic spiral, they used some other type of spiral, which did not have the equal-camming-angle property, which is unique to the Exp/Log spiral. Those Aussie cams would not hold properly, and the word got out, around the Valley, that they were unsafe.
That was the first time that I became aware that it was possible to make cams that would not be safe. Cams look simple enough, especially the small ones, but there are myriad details that have to be addressed and taken into account.
BD's recent/prior quality control problems with making cams in China is a testament to that statement.
As an aside, my AutoCAD program will not generate an Exp/Log spiral, only an Archimedes spiral. My Microstation CAD program will generate a proper Exp/Log spiral from its parameters.
My guess is the Australian guys in 1983 trusted their computer to get the spiral right, which is not usually a good idea.
Makes my mouth water looking at these fantastic gadgets, and remembering back to my early days in the valley, when we had to work our way up the grades which involved a lot of trembling up the wide sections of climbs with little to no pro at all. Before tube chocks and long before cams, even citizen testpieces like Midterm, Vendetta, Twilight Zone, Right side of the Hourglass, left side of the Slack, Right side of Absolutely Free, Ahab, Center route of the Slack, The Cleft, LA Chimney, Crack of Doom, even Sacherer Cracker, all had wide stuff you basically had to run out. Easy stuff like Chingando was okay because, as we used to say, your knee was the protection, because a good knee lock was unlikely to just blow out. But those were exciting times.
After a few initial efforts of scaring myself stiff, I wouldn't go up on one of those hard wide routes unless I felt like I could solo it. Keeps your learning curve pretty flat.
These tools make it a much saner game, and probably saved more than a few lives. Strange and fantastic how a personal piece of gear, like a well-worn big cam, is a talisman to our past.