[TheForge] treadle hammer design (was: treadle hammer anvils)

[DragonsWatch]

I have looked at the designs of several different styles of treadle hammer.  And they all seem to have one thing in common, some sort of lever and large springs which lift the hammer, and a treadle to over come the springs and lower the hammer.  So I ask, what would be the result if the springs were replaced with a weight great enough to balance the hammer.  Then a light spring could lift the hammer.  Say a conventional design has a hammer of 50# and the operator can accelerate that weight to say 5 fps and the travel is 8 inches.  You would have an
impact of XXX pounds per sq. inch.  If you had a hammer where the head was balanced, say 25# hammer and 25# counterweight, would it not strike at the same pounds per sq. inch when moving at 5 fps?
This does require the ram and the weight be rigid to each other.  The point being is that you still have 50# of mass in motion, and the energy is transferred in the blow, not in the motion of the head.  Seems somewhere it is written that a mass in motion will remain in motion, or something like that.   Just something to think about.  I'm sure I am over looking some obvious law of physics that says this is not how things work.

Larry