hydraulic press motor and other stuff

You only have an 8 inch stroke cylinder.

consider going larger, let's say you want to do a feather pattern, you need as much tool length as you do billet height plus a little wiggle to get er in.

Also when you go larger, get a larger rod diameter
I saw some 5x12x2.5 DA on three for $250, if you for 5x12x3 DA the price doubles.

A C face allows you to mount the pump to the motor easily, you could go without, but then have to make up some sort of mounts.
I think 5 HP is small.

Get Baston's book it gives you explanations and calculations
, or go to a web page that plugs numbers in and calculates all the specs but going from memory five is small 7 Hp and 10 is better.
 
Well, save some money and buy the pump from Surplus Center with your cylinder: https://www.surpluscenter.com/Hydra...s/11-GPM-2-Stage-Hydraulic-Pump-9-7503-11.axd
What you're proposing to build is essentially the same as my press, just with a slightly larger cylinder, so it will travel slower and have more tonnage. I'm running the above pump with a 3600 RPM 5hp TEFC motor and a 4.5" cylinder. C-Face with a base is easiest for this application. You mount the motor to your press with the base, then mount the pump to the C-Face with a standard mount meant for the application using 3 piece flexible jaw couplings.


Would a 7hp or 10hp press be better? Sure. JT's 10hp press can work circles around mine. Is it necessary? I don't think so (but I will be building a 10hp eventually.) IMO 5hp 4.5"-5" cylinder at 2600 psi and ~.2 ci pump displacement is around the minimum of "is this worth doing." Smaller will still work, especially with smaller dies, but past this point you're talking about doing more work faster and not so much about what work can be done.
 
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So would i be better off with a 4" or 4.5" cylinder with a 5hp? From my understanding, speed is more important than tonnage right?
 
It's splitting hairs I think.

.22 ci @ 3600 RPM is 792 cubic inches per minute, or 13.2 ci per second. A 4.5" cylinder is 15.90 cubic inches per inch of travel. 13.2/15.9= .83 inches per second (in high pressure). This makes 20 tons at 2500 psi and requires 5hp.

A 5" cylinder is 19.63 ci per inch, so at 13.2 ci per second moves .67 inches per second. This makes 24.5 tons at 2500 psi and requires 5hp.

When deciding between a 4.5 and 5" cylinder utilizing the same pump and motor, I'd just pick the one that's the best cost/design form for you. Or, what are you going to be doing the most? If you're intending to mostly reduce big chunks of barstock without regard to pattern distortion, I think that more tonnage is more beneficial. However if you're going to be making damascus or san mai and mostly pressing thinner cross sections, I think speed is more beneficial because of how fast the heat is sucked out of those cross sections compared to big chunks.

Regardless only buy a pump when you know the displacement of the stages. If all they say is "11 gpm" you don't really know exactly what you're getting and can't do the math. Surplus center sells right now two different "2 stage 11 gpm" pumps. One is .11 displacement in high pressure, the other is .22 displacement in high pressure. They're only 11 GPM in low pressure which is almost irrelevant.
 
Shush, I told my wife my big press build was necessary. If I was doing the build around a 5hp motor this is how I would do it.

Motor = 5hp, 1745rpm
Cylinder = 4.5” bore, 2” ram
Pump = 2500psi @ .45 in^3/rev

This gives you .75”/sec down and .93”/sec up. This setup puts out 19.88 tons. Remember pumps are not 100% efferent so with a good pump your getting around 90% of the fluid it says. Also it’s worth getting a good quality motor bevaus there is allways a little extra HP hiding in there. For exzample I did the math for my 10hp at 2500psi And after it was built I slowly bumped the pressure up to see what the motor could actually handle. I’m now sitting at 3000psi and my motor does not mind. But if I did the calculation for 3,000psi at the beginning then I would be stuck with a lower volume pump and could not get that extra umph out of the motor. Also the lower speed motor is sure nice for the lower noise. It would be a toss up weather to go 2 stage or single stage. I think 5hp is on the edge of being worth it to go single stage. You won’t be dazzled by blazing fast speed but you also won’t have the delay in switching from low to high pressure. Plus I think (don’t really know) single stage pumps are build better and more efficient. Here is a screen shot of how I came up with your numbers

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Not necessarily. The 16 gpm 2 stage pumps I see are still .192 - .220 ci displacement in high pressure. They're only 16 gpm in low pressure. GPM is kind of meaningless. It's all about the displacement of the pump. Displacement x RPM / cylinder area is what determines ram speed. Displacement x RPM at a particular pressure is what determines HP requirements.
 
I think most 2 stage pumps are calculated at 3500rpm as default. But if you want a quieter press then run the pump at the slower 1750 rpm. But that also means a 2 stage pump that’s rated at 3500 rpm will put out half the GPM. Like John said GPM is just a function of pump displacement per revaluation times the rpm of the motor. But if you can swing it I would jump up to a 7.5hp motor is you can. That is a quite common size for 240v singlr phase and really bumps up the performance. 10hp are like hens teeth in 240v single phase especially used. You can find them new but get out the lube and bend over. If I was going 7.5hp I would defently go single stage pump and calculate for 20 tons and enjoy the added speed.
 
I guess im confused on the ci displacement/gpm stuff. And probably other stuff too ha. The 11gpm motor from surplus center you linked, that would work with either a 1750 or 3500rpm motor right? And a 1750motor is quieter, with half the GPM, but does that slow the speed or lower the tonnage? Ill see what i can find on a 7-10hp.
 
Ok. Displacement is the volume of fluid moved per revolution. Volume determines speed. A 1 cubic inch per rev pump hooked to a 1750 rpm motor moves 1750 cubic inches of fluid per minute. 3600 rpm moves 3600 cubic inches.

Simple enough right? GPM is just converting cubic inches to gallons. It's meaningless and confuses the math unnecessarily.

Pressure is what makes tonnage. Tonnage is just the product of the cylinder area and system pressure. The work causes the pressure. A pump is just happy as can be to shuffle along the fluid with nominally low system pressure. It's the resistance of the work being done that increases pressure like putting your thumb over the garden hose. Pressure increased, volume stayed the same, and the result is increased spray distance.

Work over time
This is where HP comes in to play. Think of the pump as your transmission and the cylinder as the rear end. The motor is the engine. If you have a 5hp engine, you can do 5hp of work per unit of time. If you increase the cylinder size it's like changing the rear end gear ratio to a lower one. For a given engine speed, it moves slower than a higher geared rear end, but with more power than a higher geared rear end. Same with the pump, the transmission gear ratio.

Your 5hp motor/engine can do X work per unit of time so it's the product of power and time. Power is the pressure like torque is in the car analogy. The more pressure you need per unit of time, the more HP required to do it. So again, lower gearing slows the system but increases power for a set amount of HP.

Make sense?

I've given you the recipe for my press and the theory behind how it all works. JT takes it further with efficiency and fluid velocity relative to hose path. I don't take that into account. It's not that that stuff isn't real, to use my car analogy, it's like taking the engine torque gear ratio discussion and throwing in tires and clutch slip. Makes the discussion harder to have, to predict final results more accurately, but adds little to gross capability.

So, to answer your question, a 3600 rpm motor turning a .22 displacement pump does what we want. If you want to half the RPM to make it quieter you need to double the displacement (.44) to get the same result. Changing the RPM and leaving everything else constant changes the speed. Pressure (tonnage) doesn't change.
 
Hey I quite like the fine nit picky details lol. But yeah we have not even talked about volumetric hose expansion, fluid velocity and pressure drop across fittings lol. Just make sure you ask all your questions and show us what your buying befor you do. We could save you from a costly or dangerous build.

Lets see if we can explain it another way. Pick up a rock and throw it as had as you can. Now pick up a rock twice the size and also throw it as had as you can. Now excluding the ballistic coaficent and sectional density of the rocks you can expect the bigger rock to go half as far with the same amount of energy you used. So everything is a balance. if you double the motor speed then you need to cut the volume moved in half. If you double the pressure then you need to cut the volume moved in half and vise a versa. Cylinder speed is just how fast the bore of the cylinder fills up from the volume the pump puts out. If you make the cylinder larger in Diamater then it fills slower but has higher tons because there is more square inches for the fluid to push on. That’s all psi means, pounds per square inch. So the more square inches you have the more total pounds of force on that surface. What’s funny is when you start doing the math and you find out that if you set a gole for tons then pump volume and cylinder size are kinda fluid. If you increase the cylinder size you can decrease the pump psi and increase the volume output and still have the same tons and ram speed.

So a good place to start is nail down 2 solid numbers first. A how many tons do you want and B how much HP do you have. After that everything falls into place and can be moved one way or another. if say you find a screaming deal on a 6” cylinder you can increes the pump out put and drop the pump psi. You will still have your set tonnage and IPS ram speed to handle the set HP you have.
 
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Yep. Much easier to level a 3 legged stool cutting two legs instead of all 3.
 
You can get by cheaper. C Face makes it convenient with premade pump mounts, mine is a base mount motor and I made a mount for my pump. That's your call and what you want to fabricate. Otherwise yes, that would be a great motor. Comparitively a compressor duty 5hp base mount that I bought was $200.
 
My mount was a big chunk of 1/2” thick 6” angle iron.
 
I mispoke in my second post. My motor is not TEFC. It's open. It's segregated from my grinding room.
 
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