I need some hydraulic advice/info

K

Kev

Well-Known Member
I’ve more or less decided on making my own hydraulic forging press. The problem is I know nothing about hydraulics.
Through limited research I’ve decided on a 5” cylinder with 8” of travel. That seems more than adequate for safety and strength, please correct me if I’m wrong.
The motor will be 220V and I haven’t decided on 3hp or 5hp. I assume pump size dictates that but I don’t know what size (gpm) pump I should go with.
Given all that I will also need some advice on fluid reservoir size.
The valving has me stumped. I think it’s an info overload and there seems to be a million opinions on what style works best.

Also I would like to know what part of the equation needs to be adjusted if you are after more speed or power or both. When this is through I’d like to have a working knowledge of this stuff.

Thanks in advance.
 
You gonna have fun building a press. With your 5" cylinder you'll have around 25 ton at a normal 2500 psi. Here's a site to calculate tonnage: https://www.baumhydraulics.com/images/calculators/cyl_calc.htm

You'd like around 3"/sec travel speed: https://www.baumhydraulics.com/images/calculators/cyl_speed.htm

The typical pump you'll find with bea 2 speed pump - fast speed up to around 600 pis, then switching to low gear for high power. This 16/3.5 GPM pump is a nice pump, note the 16 gpm spec is at 3600 rpm so keep that in mind when looking at motors. It seems that most hydraulic pumps are spec'd at 3600 rpm. If using a 1750 rpm motor this pump would be only an 8 gpm pump. I suspect you'll need 5hp for sure on a 25 ton press. 3hp is good for 16 ton.

With this calculator the motor hp can be calculated.

You would use the GPM of pump at the high pressure, which would be 3.5 GPM for the above pump giving a 3.3hp requirement for 2500 psi (25 ton w/5" cylinder)

16 GPM 2 Stage Hydraulic Pump Bucher Wuxi CBNA-13/4.2 | 2 Stage (Log Splitter) Pumps | Hydraulic Pumps | Hydraulics | www.surpluscenter.com

16 GPM 2 Stage Hydraulic Pump Bucher Wuxi CBNA-13/4.2, 2 Stage (Log Splitter) Pumps, 16 GPM 2 STAGE HYD PUMP Brand new, BUCHER WUXI two stage HI/LOBucher Wuxi,CBNA-13/4.2 ,
www.surpluscenter.com

Here's some specs from the Coal Iron 25 ton press. I'm sure 10 gallon tank is sufficient, but 15 gal won't cost much more and if using the press high duty cycle it will help keep the oil cooler.
  • 5HP TEFC Motor
  • 10 Gallon Reservoir
  • 13 GPM 2-Stage Pump
  • 8" Stroke - 11.25" Daylight
While I've got issues with Coal Iron press folks due to the press I purchased from them - sold as a 12 ton press, but is only a 9 ton due to the 3" cylinder it came with. They do have some good designs. Be sure to include a decent pressure gauge to monitor pressure along with a filter.

Any other questions just holler - BTW, are you looking at a "C" or "H" frame?
 
Thank you very much for the information. Very very helpful.

I think I’m gonna go with an H-frame. What it gives in strength I find as a huge plus. I’m more than comfortable with the fabrication so I think it should be fairly straight forward.
 
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