Bill, I saw your numbers (thanks) and have spent a little time with them. I was trying to see what placements would give you a 90 degree or vertical opening. When you switched from the 90 degree arms to the boomerang style, it threw my model off and I don't have all the numbers I need. I have almost reverse computed the rest of your numbers. So, here is roughly what it would take to go vertical.
The front cylinder rod pin would have to be moved forward approximately 5 inches to give you a C-D dimension of 18" or so. Looks doable, hard to tell (except that those c-clamps seem to missing now /forums/images/graemlins/grin.gif).
The rear cylinder pin would have to about 4" behind and about 6" above the grapple arm pivots.
As for crushing cars, I understand that. I was thinking since your loader can probably lift 2,000 lbs+, it would be nice if you could hold something clamped vertically as heavy as you can lift. I looks like when your grapple is open 4" you still have about 1100 lbs of force, and around 550 lbs at 2". So I guess this plenty. You probably won't run across a 1000 lb rock or piece of steel that thin that needs lifting vertically, so it should be fine.
Anyway, playing with the numbers has been quite enlightening.
Nice project! I hope I make it into a grapple someday.
