> So, how hard do you have to pull on the handle to get
> 20 tons of pressure?
I don't know a number, but it's easy for me. I would guess that Richard's
comment is based more on the number of strokes it takes to do anything
useful, which is a bunch.
> but I guess you could
> calculate the total leverage and know the relationship
> between force on the jack handle to force at the
Easy enough to measure the ratio of movement, which should also be the ratio
of pressure (ignoring friction).
If 100 pounds force on the handle (which feels about right to me) will get
you 40,000 pounds (20 tons) at the ram, that makes the ratio 400:1. Which
means that 24" movement at the handle will get you about .060" movement at
the ram, whether it's loaded or not.
This is why better quality presses usually have some sort of fast, fine
adjustment for unloaded ram position.