Forge Press Build Questions

[Itsnick]

Hello,

I'm currently in the process of designing a press. I picked up James Batson's book "Build your own hydraulic press" which has lots of great info! Just a couple questions for those more knowledgeable than me. I have access to two 3.25" bore, 1.25" rod cylinders for the build. I'm considering using them but could also go the more traditional route and buy a 5" cylinder. Are there any issues running two cylinders? Anything special needed to get them to run simultaneously? If my thinking is correct, I'd just need to double my figures for speed, pump and motor size? So, a 16gpm pump will run both cylinders at 1.85"/sec and require 6 hp? My math could be way off, please correct me if so! 

 

thanks for any help!

Nick

 

[KenH]

Hello Nick, I know it's been a month since you asked the question, but I just now saw the thread with no other responses.  I'm surprised with the lack of response - this forum is usually a very helpful bunch.  I am NOT a press expert at all, not like some of the other folks here.  I've seen other presses with dual cylinders, and I sorta like the idea.  A bit more complex, but you've got them on hand already and that should more than offset the extra cost of hose 'n fittings.  From what I remember (very poor memory here) about the only thing you'd need to be concerned about is running the main high pressure hose close to cylinders, then have the "Y" split to be equal distance between the "Y" to each cylinder.

Another point, your 16 gpm pump is "most likely" a 2 stage pump, it's rated 16 gpm at low pressure, up to around 500 to 700 psi, then it goes to low GPM, perhaps 3 or 4 gpm at high pressure.  This allows the press (or log splitter) to move rapidly until resistance is met, then switch to low flow at high pressure.

Good luck, and I'd like to hear how things are going with the press.  I've got a Coal Iron press they call a "12 ton", but it's actually only a 9 ton since they're using a 3" cylinder at spec'd 2550 psi.  When I got my press it was only 2250 psi giving 8 ton.  While it did work "pretty good", I paid for 12 ton and really felt they shouldn't be false advertising like that.  I wound up changing to a 4" cylinder and running at lower psi for safety to have 14 ton.

Ken H>

[bubba682]

First time i seen this post ,when i built mine i run a single 5'' cyl with a 16 gpm 2 stage pump and a 5hp motor i'm not great with the math but mine is fast and i think we figured 19 ton but it does what i want it to do.In my experience i like fast over big power i don't need big power but if your a full time guy then two cyls maybe the way to go for your needs.I'm not a hydraulics guy but for making damascus speed is where its at in my opinion and your die designs are real important as well. I use my press for making every thing from  bowls to axes i got a 33lb anang power hammer i barley use i;m considering selling cause the press is so flexible and i make all my own dies.If i can help ya i will...  

[KenH]

With a 5" cylinder and 5hp motor you've got PLENTY of power for sure.  What RPM is the motor?  What RPM is the pump rated at 16 GPM?

The "12 ton" Coal Iron press I've got has a pump spec'd at 13 GPM, but that's at 3600 rpm.  Since it's got an 1800 RPM motor that gives a 6.5 GPM pump at low pressure, then it kicks into low for a much less volume flow for high pressure which is normal for 2 stage pumps.

I agree with you how useful the press is - I know some folks say you need both, power hammer and press.  I do think my first choice by far is the press.

I think it's ok to post these links here, they are VERY helpful for press calculations.

To calculate the press tons:  https://www.baumhydraulics.com/images/calculators/cyl_calc.htm

To calculate ram speed:  https://www.baumhydraulics.com/images/calculators/cyl_speed.htm

 

 

 

 

 

 

 

[bubba682]

The rpm on the motor is 1750 i think i'll have to check in the morn now lol i have no idea on the pump but its all based off a 20 ton log splitter my cyl has a 10'' stroke and its fast.I went to a hydraulics shop told them the speed and tonnage i wanted they sold me what i needed.I didn't waste my time trying to frankenstein a system together some guys have luck doing that but thats usually not me.I looked at a two cyl system but in the end i didn't want the extra cost and i wanted a small mobile system because my shop is only 24x24 and i do alot of fabrication in it so theres other gear to contend with.Whats the price you paid for your sys if ya don't mind me askin all in for me with parts and steel was 1600 and change.

[KenH]

I'd LOVE to find a pump spec'd at 2,000 rpm or so to increase the flow rate of my press.  If your pump is an 1800 rpm spec'd at 16 gpm with your 5" cylinder it would give you ~3 inches/sec travel speed which is pretty fast.  My press with 4" cylinder calculates out to about 2"/sec which is "ok", but would admire to be a tad faster.  A pump of 10 to 12 GPM would be just right.  That wouldn't give any more tons, but faster travel.  Since the die is usually not much more than 2" away from hot iron that's only 1 second travel time so it does work ok.

I also wanted a small mobile press since my work area in in the backyard, and didn't wish to leave press outside all the time, so I opt'd for the Coal Iron 12 ton mounted on a cart that I roll outside when in use, and back inside when not used.

You asked about cost - I purchased the Coal Iron 12 ton press so it was around $3200 shipped including the cart when I ordered a yr or so ago.  I added pressure gauge and the 4" ram instead of the 3" ram it comes with, which only gives 9 ton at spec'd 2550 psi.  I was only getting 8 ton since the pressure was set low at 2250 psi.  I was amazed how well it worked for only 8 ton.  With the 4" cylinder I'm comfortable with pushing the frame to 14 ton.  Your cost of $1600 is about what I calculate cost to build a 16 to 20 ton press, especially if using the "H" frame style.  I've got all the steel to build a copy of the Coal Iron "H" frame press using 3" angle rather than the 2" angle they use.  I'd be very comfortable with 16 ton (maybe 18?) {g} with the new frame.  This would require purchasing a new pump, motor, and control valve along with the various hoses 'n fittings.  I'm thinking around another $800 to $1K to have a complete new press.  BUT - that would weight a good bit more than the current press and be harder for me to roll in 'n out of storage is why I've not done it.....  yet {g}.

Had I known half of what I know now I would have built the press, but didn't know anything at the time.  The press has been a good learning experience for me.

Bubba, I've enjoyed chatting with you on this thread and exchanging ideas and knowledge.

 

[bubba682]

 MY press is a h frame and like you i didn't know much about presses my major mistake on the build was using 4''x1/4 square tubing its heavy but managable on the concrete floor of the shop.If i ever do another frame it will be 2''x1/4 so half the weight of what i got now.Lastly my speed is right around 4'' a sec so i lucked out lol and i enjoyed the chat as well...