pto driven log splitter

[MadDog]

Lots of interesting ideas surfacing here...Razorback, I haven't meant to hijack your thread but I think we are on the same hunt anyway.

I don't need to split longer and later convert to the lengths customers might want because I am going to use it non-commercially for myself and 22" or shorter logs are all I need for my various stoves/fireplaces. I am going to use a 5x24 cylinder with a 2.5" rod, which should be plenty strong enough to resist bending over it's length.

Hibeam, the pump will not mount directly to the tractor. It will be a 2 stage Barnes pump. The tractor pto will connect, via a pto shaft to an increasing gearbox that will take the rpm from 540 to 1065 + or -. The output side of the gearbox will have a double belt, 9" pulley wheel, transmitting power to a 2.75" pulley on the pump input. That way I will have the pump running at about 3500 rpm from the tractor pto at 540. The pump will be mounted on a pivot to permit adjustment of belt tension.

The Barnes 28 gpm pump rated speed is 3500 rpm (max is 4000) and can deliver 28 gpm at low pressure (approx 750 psi) or about 1/4 that at high pressure (up to 3000psi). I plan to set the relief on the valve at 2750 psi, as it is rated for up to 3000psi.

By my calculations, I will require 14.1 pto hp to run the pump at high pressure at 2750 psi and 7 gpm and 12.9 pto hp to run at low pressure at 750 psi and 28 gpm, assuming the spec'd 85% pump efficiency. With 22 pto hp at 540 rpm, I should have power to spare to run the 28 gpm 2 stage pump in both low and high pressure pump configurations.

This output, applied to a 5" bore cylinder, should yield ram travel rates of 5.4"/sec in low pressure mode and 1.4"/sec at high pressure. For my non-commercial purposes (and taking into account that I am an impatient old codger /forums/images/graemlins/grin.gif ) those should be acceptable splitting speeds, even for pretty heavy stuff.

At any rate, that's the way I am planning it. The idea is to end up with a splitter that would cost $4-6k, if purchased from a quality mfr like Timberwolf, at a materials cost of something around, or hopefully under, $2k (plus the fun of building it /forums/images/graemlins/wink.gif )

Frankly, the biggest challenge in this project is going to be making certain that the welds (and particularly those that anchor the cylinder and the wedge) are sufficiently strong to take the 27 tons of force that the cylinder will be capable of applying to a log. I guess I am going to have to become a competent welder in a hurry.....

...stay tuned for further bullitins - preferably not "mad dog quartered by homemade splitter." /forums/images/graemlins/grin.gif

 

[PILOON]

erich,
"It is definitely a project that will give you a taste of the power of hydraulics."

Sure will!

My homemade 3PT splitter used the MT180D pump (3.4gpm@2700rpm) and the cylinder is 4.5".
Kinda slow, but acceptable vs axe or maul for my usage.

But POWER to spare.
Once , for the fun of it (and kinda to show off my welds) I placed a 6" or so hard maple sideways.
The engine never even groaned, the 8" channel twisted a bit and we heard a loud twang when the log seperated into 2 lengths.

I think my welds passed the test! Awsome.

I made my wedge with about a 30 deg angle and rarely run more than 50-60% of length for a split in most wood.

 

[Highbeam]

"I don't know that I would want the tractor setting there running at full rated RPM the whole while I am splitting wood. Here is where a 2 speed PTO is nice. Mine is selectable at either 540/1000 RPM. I can select 1000 RPM and then run the engine at around half the rated engine RPM to get 540 RPM on the PTO shaft. I am of course getting a lower HP to the PTO, but if it is enough to do the job... "

My Kioti has the 1000/540 rpm PTO selector too. I would think there should be a hydro pump out there that runs at 540 for this purpose. Then again, the most common application of a hydro pump is attached to the air cooled briggs type single governed at 3600 rpm which is equal to 60 hertz which is equal to the frequency of the alternating current feeding my computer. I guess the 540 rpm is an oddball. I like the hum of a tractor engine at pto rpm when mowing and using all the power but for splitting we're talking about hours of the drone while working beside the machine.

 

[jimmysisson]

MadDog - are you going to mount the pulley to the Barnes pump? Are they made to take an axial load? Might be safer to run the pulley to a jackshaft, then one of the shock-absorbing couplers from jackshaft to pump. No sideways strain on the pump shaft that way. Too bad you can't find a gearbox that will do the whole speed increase by itself, to cut down on the mechanical complexity. Splitters operate in messy conditions all the time, and belt shrouds, etc. will need to be looked after.
Keep us up to date.
Jim

 

[jeffinsgf]

I have been watching this thread for several days, and as the discussion of the design evolves, I have to wonder, How much speed do you need?

I don't understand the desire to use a separate PTO driven hydraulic pump when you have tractor hydraulics right there. In other discussions I have read that systems that use the tractor hydraulics are a little slow. But you have to pick up the split pieces, stack them and get the next piece ready to put in the splitter --- surely it will cycle by then, won't it? Maybe it is my age, but I don't need anything faster than I am or more complex than it needs to be. I'm leaning toward a SplitFire or an Iron & Oak unit that uses the tractor hydraulics. Or, if I decide to build my own, it will be a copy of the Iron & Oak.

 

[erich]

Jeffinsgf,

I think you make a good point. With two kids out of the nest and one soon to go off to school it will soon be just me and the dog splitting wood. Neither one of us work too fast. But we do enjoy being out there doing the work.

I used to marvel at the neighbor who made my splitter. He felled, cut, split, and delivered 150 - 200 cords a year from his retirement until he was almost eighty by himself with no helpers. You could set your watch by him. In the woods at eight, back for dinner at noon, back in the woods at one and home for supper at five. If you watched him in the woods he didn't look like he was moving very fast. If you tried to keep up he would work you in to the ground.

Someone mentioned using a small engine for the splitter so the tractor was still available for other chores. I guess that's where I am spoiled. I have my tractor an MF 35 and the family farm tractor an MH 50 to power the splitter. I have had to use the loader to lift some big oak logs onto the splitter from time to time and having two tractors is a blessing

I am interested in seeing how it all comes together especially the power transmission to the pump. I really like this site for all the clever ideas that come up.

Mad Dog Where are you located in Massachusetts? If I get some trees down soon you could check out my splitter in action. Is it obvious that I'm looking for free labor or what /forums/images/graemlins/smile.gif

Eric

 

[MadDog]

This is turning into almost as much fun a building the splitter is going to be.

Jim: Your concern about mounting the pulley directly to the pump robor occurred to me. I was thinking of either using a jackshaft and coupling or supporting the outer end of the pump's arbor in a pillow block bearing.

Jeffinsgf: My tractor hydraulic pump (exclusive of the separate power steering pump) outputs about only about 7gpm and I am planning on using a pretty big cylinder (5" bore) in order to produce enough force to deal with large logs. At that rate, I would have a ram speed of about 1.4"/sec so that, to split a 24" log would take about 17 seconds, and about the same to recycle the ram again. at age 65, I probably don't move that fast either ( /forums/images/graemlins/grin.gif ) but that's a bit too much waitin' around for my taste. Of course, I don't HAVE to work any faster than I want, but this way, the splitter should be able to keep up with whatever's comfortable for me.

In any case, the parts aren't that expensive (certainly not compared to buying even a splitter with considerably less in the way of performance specs) so why not do it right? /forums/images/graemlins/wink.gif

Erich: I'm mainly located in Randolph, just South of Boston, but I have a summer/weekend place in Alford, right on the New York state line, with about 30 acres of nice woods, from which I plan to get most of my firewood. ...should be able to make out OK by taking dead-standing and deadfalls without having to cut any healthy trees. About 20 yrs ago we had a tornado touch down on top of our hill. I've been using what it knocked over ever since, although what was left outside isn't too useful by now.

 

[rdbrumfield]

I put these up on onother post. This is a pto splitter that I have had in use for over 20 yrs. I have run it with my 16 hp kubota on the 1000 pto speed. At that it works well. Hope it gives you some ideas.

 

[rdbrumfield]

pic 2

 

[rdbrumfield]

pic 3