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How do I build a log splitter that uses an air powered hydraulic jack (10 ton-20 ton rating? Answered

I have a125 psi rated air compressor and would like to use it to power a log splitter that I can use in my garrage with out the noise and fumes.



Best Answer 9 years ago

Get a heavy piece of rail, or super-heavy angle iron. Mount the jack sideways on the frame, with a heavy wide plate on the (elevating) end. Place a blade (like a wedge or a maul head) on the opposite end of the rail (pointing in towards the plate). The trick will be coupling the compressor to the jack. I'd say look in a Tractor Supply or Northern Tools catalogue. They'll almost definitely have an item to fit the two together.


1 year ago

A little late to the game here, but in case anyone ever stumbles on this question like I did, this is a BAD idea. It sounds like you just want to plumb air into a hydraulic cylinder, in which case, when the log splits you will have several TONS of stored energy that will get released all at once. Others have discussed this below. If you're wanting to use a Pneumatically actuated jack, that's going to be very slow, and not have enough stroke to do a decent job. If you have an actual air over oil cylinder, then it's doable but one of those will cost more than a used splitter, and your air compressor is going to burn itself up trying to keep up. If you don't want the noise, you're better off using an electric motor in place of the gas engine. You're probably not going to be able to get 12 Ton out of it even if you have a 230V circuit available, but you might be able to develop 8 ton or so, and do it pretty quietly. They also sell some electric splitters that might do a good job.

Air over hydraulics do not "fly to the limit" when mot under load. The air only cycles (more or less) like a hand pump, stroke by stroke. Unloaded, the air can cycle much faster, but the cylinder can not advance as quickly as you are suggesting. We use air over hydraulic jacks all the time, and I can safely run them up and down unloaded with no fear or danger. The hydraulic fluid, as you stated, does not noticably compress, so there is no danger of a flyaway cylinder there either. I wouldn't try to build my own air controller for the hydraulics if I were you, unless you really understand the physics well.

The reason air over hydraulics doesn't "fly off the handle" is because the flow rate of the oil is restricted by the size of the orifices that are built into the system. Without these flow restrictions, the system would slam back and forth just like a pneumatic cylinder. In other words your air over oil jacks work smoothly and safely because the components were designed for that purpose. If you rig up your own system, and fail to address this issue, the results may not be what you were looking for.

Here is one that i have put together. I found a 6" air cylinder and fabricated the rest. Here is a link to a pic and video of it.


I have some sensation that running an hydraulic jack with air is a bad idea. When the log splits the jack is going to fly forward with some force and something will slam into something else quite hard. If you have an hydraulic system(?) you might be better converting that to electric. L

The air operates an air piston in a small cylinder, which in turn operates the jack's normal hydraylic piston. One stroke of the air piston is equal to one stroke of the jack's normal lever. The limit of the jack's extension is only 6 inches. When it reaches it's limit, additional jack operation has no effect on the jack' extension. My other jacks have a bypass that pevents pumping when the jack reaches it's limit In my proposal the jack is powered by hydraulics, the air is used to operate the jack handle If more than 6 inch thrust is required to split the log, the jack screw extension can be used , or a spacer can be placed between the jack piston and the log. Thanks for all the comments. An orifice can be placed in the air line to limit the speed of the air piston if it is needed

Ah, that sounds like it could work for you. I hope you build it and show us how you did it. What's the return mechanism on this -spring? L

. To expand on that a little: Hydraulic fluid is incompressible and does not store energy within the medium. Air compresses very well and stores a lot of energy. If you build up 100-125 PSI behind your cylinder and a log splits suddenly, as L says, the ram is likely to go to the limit of its travel with considerable force. . In your application that really doesn't decrease safety very much, but it is hard on the equipment. It ends up beating itself to death. . . If compressed air is your only option, I'd look into a pneumatic screw of some sort.

. I was thinking of a screw jack/jackscrew with a pneumatic motor attached, but a Q&D search didn't turn anything up. There's bound to be someone that makes them.