I'm contemplating building a hammer. I have a motor and some of the material. I also have some heavy truck leaf springs, but I see many posts where they straighten the springs. Is that necessary? I would think that having them curved down would give a more powerful blow. Can someone explain this, please?

 

Thanks,

Jerry

I think what your seeing are on treadle hammers as aposed to helve hammers. And in reality you dont need a heavy truck spring on a helve.
The spring is there because somthing has to give. If the mechanism is built to just kis the anvil all is good untile you inteoduce a peice of steel, and i there isnt a spring to provide some give, somthing breaks. You should see what happens to a punch press when that hapens, thing small bomb, compleat with shrapnel. So the spring gives when the hammer hits the workpeice, so the drive traincan make its compleat cycle. Not realy nesisary when your leg provides the power.
On a note, two light of a spring and you can reach a point of resinence, and the hammer will flote, wile two heavy a spring and the hammer will stall, and the weekest link in the mechanism will fail.

I think he's talking about a "rusty" style hammer where a piece of spring acts as the helve.

 

I would think that straight would be better---but try it and see!  You can change it out if you don't get the performance you hoped for.

The problem of slop between the rollers which raise and lower the tup driven by the spring pack is greatly exacerbated if the springs are curved.

 

DO NOT CONSTRUCT A POWER HAMMER  WITH USED CAR SPRINGS. Extreme danger.