I have a 20 ton lever operated bottle jack mounted inside a frame that I plan to use for forging small knives.

The frame is only experimental to get a feel on how much pressure is required to squeeze leafspring-steel.

As long as the lever isn't putting up much resistance, that is, in the beginning of the squeeze, I'm not too worried.

But as the spring-steel starts to flatten, the piston movement is being restricted and the lever is getting hard

to operate pretty fast. I'm not comfortable with using all the strength I've got on the lever as long as the frame is

just an experimental frame. I have several feet of large H-beam outside the house and I plan on making a frame

as soon as the snow is gone. Let's say I manage to make a reasonably safe frame,-how much force can I apply

to the lever? This bottle jack has a safety valve built in, but I know little about how this stuff works.

Is there a chance I'll ruin the bottlejack, or can I just operate the lever with as much strength as I want provided

the frame holds up?

I'd be more worried about failure of the frame.  If it lets go it could be quite explosive. Usually there isn't much you can do to a bottle jack.  I'm sure someone with more experience in presses will  chime in.

IMO you are under powered and too SLOW to forge successfully!  In the time that you can take three or four pumps on the lever you should have your work already done for that heat!  Better with hammer and anvil than what you have IMO.

This is a poor idea it will not give you any advantage at the forge it does not have enough power or speed to move metal hot. I suggest you spend your time working at the forge you will see much more return for your efforts.  When you have established what can be done by hand using skill and experience as a guide it is then time to move on to powered forging. 

What is the frame rating? It should be more than the rating on the bottle jack otherwise you CAN easily have a failure. At high pressure like 20 ton, any failure can and will be very dangerous.

 

And there is no I do not or will not use that much force without a meter showing you exactly how much force you are applying.

 

Safety first.

Way too slow if manually operated by the time you get real pressure on it your stock is too cold to forge effectively by die quenching.

I'm afraid you just don't know enough about this to make your own hydraulic forging press safely. While we're all pretty generally happy to jump in with advice this is one of those things that we'd feel pretty guilty about hearing something went wrong on a press we helped with and someone got hurt.

 

For a few basics of the things. #1 20 tons isn't enough. #2, hand powered isn't even close to fast enough. #3 Unless you're an experienced welder have it professionally built. #4, NO, you aren't likely to be able to put enough pressure on the lever to damage the jack, they're over designed for safety's sake.

 

Do some reading in the blade section of IFI, those guys use forging presses a lot and have some good solid designs.

 

Be SAFE, there aren't enough of us around to needlessly risk losing someone.

 

Frosty The Lucky.

I did the same thing with a 20 ton bottle jack but mine was air/lever opperated. It was way to slow to get any good resaults. I found i did a lot but with the hammer and anvil. The frame i used was made out of 1/4" i beam with a 5" web and did just fine. I only used it a few times before going back to my hammer. i was really disappointed with it.

Shon