Another "I want to build a press" thread...

Bühlmann

Bühlmann

North Lake Forge
Joined
Jan 6, 2022
Messages
475
Short & sweet:

- H-style press
- 2.5 x 2.5 x 0.375" angle iron frame
- 1 x 4" cross members, ram & anvil reinforced to be 3" at die interface for additional surface area and 3" square die blanks for 90 degree utility
- 4" cylinder w/8" stroke
- 3 5 HP 1ph motor, 3600 RPM, 220V
- 11 16 gpm pump
- 18gpm open center, 1-spool, 4-way, auto-detent Prince valve
- 5 7 gal reservoir

This configuration should net me the following:

16 tons of force @ approx. 2550PSI, 3.37 3.8 IPS in high, 0.64 1.26 IPS in low


Is my head right on this? What am I missing? Thank you for any input and wisdom!

*Updated numbers to reflect accepted advice to up motor to 5hp
 
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What rpm is the motor? Most pumps seem to be rated at 3,000 or 3400 rpm. If it's an 1800 rpm motor then you're looking at half flow. Other than that, looks good. You're planning an "H" style frame?
 
Ken H> said:
What rpm is the motor? Most pumps seem to be rated at 3,000 or 3400 rpm. If it's an 1800 rpm motor then you're looking at half flow. Other than that, looks good. You're planning an "H" style frame?
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Good catch, Ken. It's a 3600 RPM motor. Yes, an H-frame press.
 
Just me but I would ditch the 2 stage pump. Control your retracts and you will get more work out of it as you won’t have that delay switching from high to low speed. And if your goi g to all the trouble to build a press I would do everything in my power to get at a minimum 5hp but better a 7hp motor. 10hp can be found for 240 but thy are pricy. I have ran my 10hp 3hp off a 10hp Chinese VFD and it worked but not optimal.
 
I like the 2 stage pump since it allows fast ram travel until the pressure starts building. During the high pressure stage it's provides slow travel for better control. Since it's only moving 1/4" or so at max the slow speed isn't an issue.

He's only talking 16 ton press - a 3 hp "should" build the required 2550 psi just fine. Coal Iron does use a 5hp on their 16+ ton press. I suspect that's because they use the same pump on the 25 ton press. I've got a 2hp motor on my press and it has no problem building 2550 psi on a 4" cylinder. It is an 1800 rpm motor, but other folks have reported good results with 3600 rpm 2 hp at 2550 psi for 16 tons.
 
Would it be better to get a 22gpm pump and an 1800 rpm motor. More torque that way?
 
Your 3hp 3600 RPM motor should be just fine. If you've not purchased your motor yet a 5hp would be even better and isn't much more expensive than the 3hp. Yep, if the motor hasn't been purchased I think I'd go 5hp since that's only $25 or so extra.

Please do understand the only hydraulic press I've got any experience with is the 9 ton unit (3" cylinder) I purchased from Coal Iron. I think upgraded to a 4" cylinder so I could get 12 ton advertized from it, and have pushed it a couple of times to 2550 psi with an 1800 rpm 2 hp motor just to see if it would. The Motor works good at that pressure, but does put too much strain on the frame. I doubt seriously the 2hp would work very good at 3600 rpm. I've read where other folks used a 3 hp, 3600 hp motor at 2500 psi with success.
 
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Ken H> said:
Your 3hp 3600 RPM motor should be just fine. If you've not purchased your motor yet a 5hp would be even better and isn't much more expensive than the 3hp. Yep, if the motor hasn't been purchased I think I'd go 5hp since that's only $25 or so extra.

Please do understand the only hydraulic press I've got any experience with is the 9 ton unit (3" cylinder) I purchased from Coal Iron. I think upgraded to a 4" cylinder so I could get 12 ton advertized from it, and have pushed it a couple of times to 2550 psi with an 1800 rpm 2 hp motor just to see if it would. The Motor works good at that pressure, but does put too much strain on the frame. I doubt seriously the 2hp would work very good at 3600 rpm. I've read where other folks used a 3 hp, 3600 hp motor at 2500 psi with success.
Click to expand...

Yep, I've read all of your posts on your Coal Iron experience. That's one of the things that has inspired me to tackle a build. I know everyone says bigger is better with presses and I agree, but as a hobbyist there are practical and financial limits to my endeavors. The 12-ton (8ton) Coal Iron would fit my needs well I think, with the upgrade you shared to get it to capacity for what I think I'm gonna do. So if I'm gonna go through the challenge of a build, to upgrade it to allow for growth in my own skills and capacities by beefing up the frame and hydraulics to a 16 ton system with the same footprint is kind of a simple no-brainer.

I like your idea of bumping to 5hp. That should eliminate any compromise in torque by using a 3600 rpm motor. Looks like I could bump up to a 16gpm pump with a 5hp motor too, which would increase the low stage to 1.26 IPS, all other factors being the same.
 
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One thing I will put out there is the higher the motor RPM the louder the pump by quite a lot. I went 1750 and glad I did. I have a big monster of a motor that’s 1144rpm that I wish I would if used instead.
 
This is my press and I love it. I settled on about 20 tons and put the rest into speed on a single stage pump. Make sure you do all the flow rate calculations so you pick the smallest hydraulic hoses needed. It’s a trap in thinking bigger hoses are better which thy are not. Thy will lag the system as the hose stretches and the fluid in them compresses. There is recommended flow rate for each hose and if your wanting fast response and no lag then you want to use a smaller hose.

 
JT, the higher RPM motor being more noisy I'd not considered. Since the bare motor running isn't any difference I'm surprised the higher RPM makes the press louder. For sure something to consider.

That's one heck of a press you've got there. The frame looks like it could handle 30+ tons with ease. You mention it's a 20 ton - what size cylinder are you using? A 5" cylinder would only require around 2,000 psi - nice loss pressure.
 
Thanks JT, I figured that'd be the case. I've ordered most of the components for the build, and couldn't find an 1800rpm motor configured how I wanted that was in my budget. I have a few ideas in mind to help mitigate the noise, which I was considering incorporating regardless of RPMs, but figure I'll definitely want to do that now. We'll see. That's not a major factor for me, but it is one that is worth considering.

I think I'll do a WIP for this project much like I did with my Revolution grinder build. None of it is original design by me, but my approach may be helpful to others that may hope or plan to do the same someday.
 
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