I have a 30 ton H frame press that's been collecting dirt for awhile and was thinking about getting one of those harbor freight 20 ton air bottle jacks for it. So far I've read a handful of topics for those little air hydraulic presses but everyone seems set on building their own press frame for them. Is it a wise idea to use this 30 ton frame as a 20 ton forging press host? For less then $100 and hardly any time on my hands it sounds like a great idea after seeing what these small presses do on youtube. 

I can't see a reason why not. The press is more than stout enough for a smaller jack. I'm personally not a great fan of HF tools myself as most really aren't worth the money you pay for them. I can't say about that jack, but the floor jacks I've used weren't worth wasting money on as most failed or leaked within 6 months.

I know what you mean, harbor freight usually makes me cringe but it looks like people have had luck with them. I was mainly concerned about the play in the top ram that comes down, there's maybe an      1/8" of play back and forth. Could that cause something to spit out at me?

for a forging press you need speed, count how many inches a second your jack can go to see if it is suitable

This isn't going to be a serious endeavor, just something to pass the time until I actually put time aside to build a real press. I'll be more than happy if it will squeeze a hot piece of metal faster then I can forge it by hand.

I built one. Made 2 harley chain knives on it and several random pattern Damascus knives with it.Just remember you have 20 tons of pressure.Gotta keep the work hot.

What the heck you can always use a new jack right?

Take Care

TJ Smith

I did make a 20 ton though just so you know Once your're hooked on damascus  you 've had it.