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Tractor Powered Press


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I am planning to build a hydraulic press possibly using my tractors live hydraulics for the power supply. According to Kubota, my nominal 40 HP tractor can supply 20 HP hydraulic power at 2850 PSI. The tractor has a set of quick disconnect fittings where the press can be connected. However all the external lines on the tractor are ½ inch diameter, which seems a bit small for much flow and subsequent slow piston movement? The cylinder I am planning to use is 7 inches outside diameter and has a stroke of about 12 inches. I am wondering if others have tried to use the tractors “live hydraulics” to run a press. To keep the supply and return lines short, I also wonder the wisdom of welding attach points on the press frame to interface with the tractors 3-point hitch points and back the tractor with press up to the hot shop door, next to the forge. Protection of the hydraulic lines (and the rest of the tractor’s rear end) with metal shields is also envisioned.

Comments and suggestion are welcome and appreciated.

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SS, your plan has some merit, but there are some things to be aware of. Based on my experiences with 3-point hydraulic log splitters, your 7 inch cylinder is quite large and will move fairly slowly. Should work fine for welding a billet where the cylinder only has to move a short distance, but beyond that, it will be frustratingly slow. You should be able to generate 20 tons or more of pressure. Some tractor hydraulics are better than others for this kind of application. Does yours have a hydro valve that allows continuous flow? Many don't, and that means you would have to either bungie cord the valve open, or reach over to the tractor to operate the valve. If your tractor allows for a continuous circuit, I assume you would put control valving at the press. I don't think I would worry too much about length of hydraulic hose, if flow rate through the hose is an issue, you could jump up in hose size, say from 1/2 inch to 3/4. Good luck! Take pictures to show us!

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Saratoga - your idea is exactly how I run my press. Though I have the smaller Kubota. Mine is the 2500 so only about 20 some horse.

The cylinder that I use is a Prince about 6 inches in diamater. It was the right price but really to long of a stroke. I block up the floor to it only has to travel a small distance. I didn't want the shaft to deflect and bend if there was slippage in the metal I am working.

I have attached a pricture here, but it is pretty small. I will try to get a couple other pictures and share them in the next few days.

I have some long hoses to attache the press to the tractor. I had these laying around from a roadgrader we have. The hoses were used to power the one-way cylinder to lift the V snow plow.

I used the frame that attached the V plow to the front of the grader as the frame for the press. It seems to work okay, but I do get some flex in the frame of the press. The frame is 1/2 Z steel.

I like the long hoses so the tractor can sit outside the shop and I can shut the overhead doors to keep the hum of the engine and the exhaust outside.

Also the safety of having the tractor outside and away from any potential hot metal flying anywhere makes me feel safer!

The valve I use is off a drill fill auger we had on an old farm truck. My father-in-law rigged up a simple foot pedal to run the valve. This is really handy to have your hands free.

All in all, I am happy with my press running this way and have plenty of power for what I am doing.

Let us know how you are progressing on the build.


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I asked A tractor repairman about using a log splitter on a tractor and he told me that he gets lots of work replacing hydraulic pumps on tractors from people who think they can load a tractor pump at max for extended periods.
The Tractor pump is not designed for the kind of duty cycle required for press like applications.

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I took some pictures of my press yesterday. It works very well, though I don't use it exclusively. I also have a 50# LG that makes my smithing pretty enjoyable as well.

I pressed some billets of roller chain knife blanks the same day I took these pictures. It worked very well and I hope to add some pictures later of the jelly roll blacksmith knife...if the pattern turns out.

The foot works well, however I got a thicker piece off to one side and ended up breaking the weld around the collar. I need to reweld with a better rod and get back to work.

Here is a link to the pictures - http://picasaweb.google.com/doubleydesign/HydraulicPress#

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Thanks for the helpful suggestions. I'll double check with the tractor dealer's service guy about twcoffey's concern about limiting pump life, as well as firefarm's comment about valveing and if continuous flow is available. I've sent a PM to poleframer asking about his experiences.

I don't know the actual piston diameter, but the outside diameter of the cylinder is a bit over 7 inches. Assuming the piston is 6.5 inches in diameter, and limiting max pressure to 2500 psi (tractor max is 2850 psi), that should give me a 75,000 pound push (area x pressure). I would then size the fame for 100,000 pound design load and a 1.5 safety factor. Using A36 steel yield of 30,000psi would require less than 5 square inches of frame work to resist the tensile load. I expect the bending load for the top and bottom members of an H-frame press would the critical design factor. I am thinking that 12.0 inches inside to inside dimension of the frame would be the minimum width. A C-frame press would be a bit more complex, but might be worth the added working room.

Any and all comments on the above thinking are most welcome…

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Hi Bob, and all. I'm off grid out here in oregon, and the hydraulic system came about when I got a big old sebastian lathe from a friend and was trying to figure out how to power it, as my system is really only good up to about a 1/2 hp electric motor.
I have a little yanmar rubber tracked crawler I'd been making impliments for, and had replaced the little 10 hp air cooled engine with a kubota ZB600 2 cyl, think its rated 12 hp continuous. I mounted a hydraulic motor on the lathe, ran it off an aux port, and it worked very well. So I bought another ZB600 for a few hundred (they are often used on refer trucks, or for those highway light signs) and put that in a small shed next to my shop. It's very economical to run, and does most of what I want at an idle.
Well, along came a big old 30" Parks bandsaw, and a versamil milling attachment for the lathe that I also plumbed into the system. One problem I ran into was that the bandsaw was across the shop, and the 1/2" high pressure line just didnt do it ripping through 8" oak I was working with, so I plumbed it with 3/4 black pipe, and set the pressure relief for that line at under 1000 psi, and it cuts just fine now.
Then I made myself a H frame press, that you can see in my JYH and press thread in the Hammer section. I think I'd like to change the cylinder from the 4" to more like a 6" to 8". I couldnt stop, so I made the power hammer on it, and look forward to some time off work this winter and play with some steel.
The next project in the works is a 6"x48" belt grinder, with a 12" disk, also run off hydraulic.
I guess the only suggestion would be to size your lines accordingly, friction loss really comes into play if you start running longer lines.
I have had good luck buying used hyd. motors, and valves, probably have spent the most on having hoses made, be aware that 1/2" steel hydraulic line is measured OD :( so its more like 3/8" ID, I ended up doubloing the lines from the pump to the valve bank to get everything running well. The flow control valves make for great speed controll as well, I can spin the lathe anywhere from 0 to 2000 easily, plenty of power.
I think this type of system might be a good alternative to getting a phase converter, and going 3 phase in the shop for the power hungry tools, I'm not a full time machinist, or cabinet maker, so it's not like I'm running that diesel all that much.

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Thanks poleframer for the helpful information.
I did talk to the tractor dealer’s service person about my Kubota L4610 tractor. He did confirm that using the hydraulics to run a log splitter can be a problem if the flow is cut off without a pressure relief. The pump will break up. They do sell a retrofitable option to install a remote valve with detent mounted on the fender, an additional set of QD’s, and overpressure protection for a bit less than $1000.00. Ouch!

I also got some better performance numbers for my nominal 40 HP hydrostatic drive tractor. The hydraulic system pressure is 2400 psi new and I should use 2300 psi. The free flow is 7.7 GPM and I should derate that to 6.7 GPM at max pressure. Assuming my cylinder bore is 6.5 inches, the max pressure would be 75,900 pounds and piston travel at max pressure would be 0.75 inches per second max velocity. Long, skinny hydraulic lines with tight turns would slow it down quite a bit.

So I am thinking that if I really need to spend $1K to protect the tractor, I could buy a used hydraulic electrically driven power supply for maybe the same money. Back to the drawing board.

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