Help with shop press

sharpeknives

sharpeknives

Joined
Jan 13, 2006
Messages
1,655
I have a electric/hydraulic pump from a car lift. Best I can figure is I get 2000-PSI Line pressure. What size cylinder do I need to make a decent working press? Or do I just have Junk?
 
Last edited:
figure out the square inches of your piston surface and multiply that by your PSI and that's your pressure

-Page
 
So if I have a 4" cyl at 2000 psi pressure, I have a 25,000 lbs press. is that how it works? Is that adequate?
 
You've got the basic calculation right (with rounding ;) ). That is of course just a theoretical calc and doesnt include things like head loss, etc, but close enough for estimating purposes.

With that configuration you'll only be making about 12.5 tons for your press. This is a bit on the low side and you probably wouldn't be too pleased with the performance. I'd recommend a minimum of 20 tons for a forging press. This means you'll need a bigger cylinder (5" would just about get you there), or you could put a couple cylinders together (keep them the same though).

Another big thing to not overlook is the flowrate from the pump (usually in GPM). The flowrate from the pump will affect how fast the cylinder can move up. The calculations are a little more complicated, but I can help you out with those, given the cylinder size you'd want to go with. If the pump doesn't have a high enough flow rate, the press will move way too slow to make it worth your while as a forging press.
 
here you go
4" 2x2x3.14=12.56sq inches at 2000psi (1 ton) 12.56 tons
5" 2.5x2.5x3.14=19.625 sq" at 2000psi is 19.625 tons
at 2500psi
4"=15.7 tons
5"=24.5 tons
at 3000psi which is the maximum working pressure of most pumps
4"=18.84 tons
5"=29.43 tons

a 2 stage pump is recommended for fast closing and then high pressure to do the work
smallest recommended is a 11/2.9 and 5hpgas/3.5 electric
better is a 16/3.5 at 7hpgas/ 5 electric
if you want 3000psi you need to be on the high side with your HP
 
As shown, the problem isn't generating the pressure, a HF bottle jack will develop tons of pressure, it is ram speed. Your small pump will not deliver anything even remotely close to the GPM required. It may be usable for a blade stamping press or pin press.
 
You must log in or register to reply here.
Back
Top