Inexpensive Hydraulic Power Pack for Press

[lostcause]

A question for those with knowledge and experience:

Could you use a hydraulic power pack like the ones used on automotive lifts in conjunction with a hydraulic cylinder to power an h-frame shop press? S/A pack & cylinder with spring return, or D/A pack and cylinder for power both ways? I see a lot that style around 3000psi, which would match a lot of cylinders... I'm not looking for production line use here, just the occasional home shop stuff. I didn't look at flow rates to see how slow it would be, but what else am I missing?

 

[ericm979]

If you have shop air you could replace the press's bottle jack with an air powered one. Many people have done that.

 

[lostcause]

If you have shop air you could replace the press's bottle jack with an air powered one. Many people have done that.

Certainly evaluating that option, as it's relatively straight forward, but I also want to know about the electric hydraulic option too. I'm wondering whether the air option is more of a pulse as opposed to a motor/pump being smoother? I'm likely to completely make the frame from scratch as I don't currently have a suitable size press frame. I'm planning on targeting somewhere in the 40-50 ton range and intend on having some cavity based ironworker tool options thrown in.

 

[homesteader13]

I had a Bend pack air over hydraulic unit, worked great on my big press.
And all you actually need is the unit and you can plumb that right in the existing jack on the press.
Very simple to set up. 1 air line in. 1 hydraulic line out.

Amazon.com: Mophorn Air Hydraulic Pump 1 PSI 1/2 Gal Reservoir Hydraulic Foot Pump Air Treadle Foot Actuated for Auto Body Frame Machines and Pulling Post: Home Improvement

 

[jenkinsph]

A question for those with knowledge and experience:

Could you use a hydraulic power pack like the ones used on automotive lifts in conjunction with a hydraulic cylinder to power an h-frame shop press? S/A pack & cylinder with spring return, or D/A pack and cylinder for power both ways? I see a lot that style around 3000psi, which would match a lot of cylinders... I'm not looking for production line use here, just the occasional home shop stuff. I didn't look at flow rates to see how slow it would be, but what else am I missing?

Yes you can get a 12 volt power pack with double acting hydraulic valve using a pendant switch for about $300. At 3000 psi a 6" bore cylinder will be over 42 ton capacity. I would go larger diameter and lower the pressure required because the pump will last a lot longer.

 

[BukitCase]

"I'm wondering whether the air option is more of a pulse as opposed to a motor/pump being smoother?"

I have air/hydraulic replacement cylinders on my 20 ton press AND cherry picker; BOTH exhibit the pulsing, it's more noticeable on the cherry picker, makes me a little nervous with heavier loads.

Not that big a deal on the press, most times I use the air to "sneak up on" the actual pressing function, then use the jack handle for the actual pressing operation. Best of both worlds, saves a few HUNDRED strokes on the handle VS holding a valve and watching. Plus, using the handle is so slow it's almost surgical precision.

If you decide on a pump like the previously linked one, be sure to do the math - you would want AT LEAST TWICE the reservoir capacity as the cylinder volume, preferably even more. Kind of pointless to constantly have air in a hydraulic cylinder, not to mention a destroyed pump... Steve

 

[lostcause]

Yes you can get a 12 volt power pack with double acting hydraulic valve using a pendant switch for about $300. At 3000 psi a 6" bore cylinder will be over 42 ton capacity. I would go larger diameter and lower the pressure required because the pump will last a lot longer.

That's pretty much what I had in mind - 6" bore, 6" stroke at 3000 PSI would get me where I want to be tonnage wise. I hear you about the lower pressure thing... My plan before moving out with this was to research an average daily cycle volume for car lifts and volume required per full lift and see how that relates to my weekend warrior needs and consider a lower pressure if it looked necesssary, but I really don't want to go bigger than 8" bore - if i could even find something like that.

If you decide on a pump like the previously linked one, be sure to do the math - you would want AT LEAST TWICE the reservoir capacity as the cylinder volume, preferably even more. Kind of pointless to constantly have air in a hydraulic cylinder, not to mention a destroyed pump... Steve

Yeah - As I mentioned above I was thinking a 6x6 cylinder which is about 3/4 of a gallon and most of those car lift power units are 2.5-3 gallons so I'm 3x-4x on fluid volume. Kinda why i wanted to consider one of these - they seem pretty much ideal.