Hydraulic press design question. | Power Hammers and Presses | Forum

I don't know about your side of the line, but the best place to buy hydraulic stuff in Canada, is Princess Auto (Langley, Coquitlam, Kelowna, in B.C.). They have a 6" diameter, 8" stroke, press cylinder.

Hydraulics isn't magic, it is all math. Diameter surface area = pi.R2 X hydraulic pressure = pressure. 3.1416 x 3x3 = 28.274 sq/in x 3000 psi = 84823.2 lbs/sq in. yes that is 42 tons. At 5000 psi = 141370 lbs/sq in, yes 70 tons. If you take a press tool that has less than 1 sq/in of contact surface, it multiplies again. 1/2 sq/in contact area, doubles the psi (42 tons = 84 tons or 70 tons = 140 tons psi).

If you use a two stage pump, you get the advantage of low pressure/high volume to move the ram and high pressure/low volume for the grunt. This pump is used in Log-Splitters, it works wonderful for a working press with heat. Not wasting heat, waiting for motion.

If you don't keep your press tool captive and straight you have the capability of a bullet, uncontrolled. Catastrophic results to a persons anatomy/life.

Don't be afraid of the machine, build in safety!!!!!!! If you forget for a split second, you are done!!!!

If you have a question, ask Paul Thorne (Anacortes). He has built a few and has taught workshops using Hydraulic Press'.

Todd- hopefully you picked up that one on the Seattle CL for the stupid price of 150$?~! I know- I almost was gonna go for it but I'm pretty well looking for more power and speed than the 10HP I currently have. That pump should give you the pressure I'm sure, but the flow should be checked so you're not disappointed. Surplus Center has a handy guide for $1.50 that tells you how to estimate flow based on the size of the pump or you can wait til you get it all hooked up and time your cylinder extension/retraction. Like Neil says- you don't want to be waiting there all day while your metal cools.

That's what blows me away with all the guys building 'forging presses' with enerpac pumps. Yeah, you can develop 100 tons but you'll be cold forging by the time it gets to the work~:unsure:

On your original question- I'd be looking at a 10 or 12" stroke cylinder. It was the same thing when everybody was building Kinyon air hammers ten years ago when 'the book' said use a ten in. cylinder. I went with a 14" and don't regret for a minute building in that extra stroke. So your hammer or press frame is a little taller. With tools, swages and the bending dies you'll inevtiably make, you will eat up ALOT of stroke in a hurry that you can't get back if you didn't leave enough room in the first place. On my 400$ H-frame press, the thing came with a 6" stroke so I constantly have to block up the bed to get in the working range. Some presses have moving beds. Given the choice between that or having a longer stroke- which is easier?

I really do like Batson's double angle H-frame in the new edition of his book. I was gearing up to build one based on that design until I sat and stared long at hard at the junk forklift right outside my shop. The Froklift mast is a perfect H-frame complete with a rolling carraige waiting to happen. Stay tuned:)

For 250$ ea, Larry, Really?! I'll take two.

The 'book' we refer to is "How to build a hydraulic forging press" by Dr. Jim Batson, a retired rocket scientist from Alabama. It can be hard to get a hold of. On iforge they have two dead links and one that I haven't tried in too long: [EMAIL=larbooks@impulse.net]larbooks@impulse.net[/EMAIL]

norm has lots of BS books.

Good point on not needing the two stage, Tom. Some people have had no problems running the log splitter pumps for 15 years without fail. I blew one up in five minutes because I had a few too many pounds of thrust on the lovejoy coupler. Totally PO'd me after spending weeks setting up the pump/tank . I do think the single stage pumps are more robust. I haven't tried the piston or vane pumps yet but I could be convinced. Supposedly they can be alot quieter- something gear pumps don't share.