Thanks for the input guys.
Rlarkin, I don't think it is needed if everything is solid enough, there shouldn't be any twisting action or undo stress. I don't think the helve arm needs to flex, atleast not with a foot powered one.
Thomas, that is a good idea. Trying to keep it as simple as can be, If I were to make it with the screw adjust I would have to make it very very nice with the turn handle at a right angle coming to the front of the machine, I'll keep it in mind as a possible mod, or for when I build another, larger one. Part of the design idea for this one is lift on the truck and go, simple light yet hard hitter for basic forging processes, simple to build and fix if needed. I still haven't figured the exact position of the link between the pedal and helve itself just yet, that will come when it is built.
Frosty, cause I already built one of those
. I have the treadle for the more advanced tooling work, just want this one to do one thing, basic hard forging. Draw tapers, draw length IE tong reins, work down larger bars, stuff like that.