[sanddrag]

I've used brakes larger and heavier than that one, with longer legs, and on thicker pieces, I've still had to have a couple buddies pulling on the back to keep from it tipping forward (floor standing unit, not bolted down). It is definitely to your advantage to have the machine as secure as possible. I have seen brakes of the style you linked above bolted to large workbenches, made of 4x4s and a 4x8 sheet of plywood for the top, and that seems to work fine. Since your stand is already made, it looks like you want to proceed down this route. Whatever base you make for it, just make sure it has a really good footprint. If 700+ lbs tipped over onto your leg, you better start looking for a set of wheels.