Here's my shop-made clamps. I made 6 of them for about $30 worth of hardware. I used 5/8" threaded rods which I bought at Lowes. The 1/2" pins were cut from 1/2" bolts. I used 6/4 white oak - only because that's what I had that was expendable. They have a 42" clamping capacity. They work okay, but the oak flexes a bit when tightened; thereby making the jaws a bit off square when tightened heavily. I guess I could reinforce them. The basic plans for these is in one of the Wood magazines, but I dunno which issue. The rods in the plans call for Acme rods (the kind of coarse threaded rods used on vices and good commercial clamps) but these are very expensive, and hard to find. Would I make these again? Probably not, but they are nice when a long clamp is needed.