Design question

My question: How does one go about figuring out attachment points and ram stroke to get full travel without binding?

Take a look at the link above. Lotsa homebuilt thumbs and such.

Probably the easyist is to copy a working unit. If your not selling the unit then there's not usually a problem.

If not, then graph paper and a compass working close to scale as possible and use swing arcs to prove your design.

Once the paper model proves it's self, then use some 1/8"x1" flat bar and 1/4" bolts to make a real size model on the unit to confirm your deminsions. Once that works out, then it's time to build the real McCoy :)

$25 worth of scrap flat bar is really cheap when comparred to $300 worth of good steel with a mistake.

T_Bone