thoughts on engineering my tractor powered splitter

[ditchrider]

I bought a wood splitter for my tractor on a farm sale 15 years ago. It was rebuilt twice and it's aging again. It is and was operated off of the tractor's hydraulics which need 1500+ rpm to function with proper flow and pressure.

Problem 1: My source of wood is BIG A@# trees, minimum 18" but normally 30" plus diameter. Cottonwood, Chinese Elm (yes it is Chinese Elm) and Ash (not that big, but can be tough). I also get a lot of older fallen trees in the BIG category. Mostly elm and cottonwood and big and often crotchy. Tough splitting. I try to keep my sawcuts about 17-19 inches to max out my stove's firebox.

Problem 2: The tractor. I have five powerplants sitting around in the winter. 70-180 horsepower. Powerwise I don't NEED to run any of the tractors at more than 1000 engine rpm, but to get the hydraulic fluid from the tractor cooperating with the cylinder I need at least 1500 engine rpm on every machine but the 180hp tractor. That one has the flow and pressure and closed center hydraulics to run near idle. Nonetheless rapping up the tractor burns fuel, creates noise and it's hard to manage my crew of three tots. Don't get me wrong, there is some Tim (the toolman) Taylor in me, but the diesel fuel is just wasted when 1000 rpm or less will do. Free heat isn't free by my rule when fuel is wasted, my ears are ringing and the rest of my body is buzzing and my tots are tired of my lack of patience, which results from all three.

Problem 3: The wood. Refer to problem 1 and multiply because it's normally wet. Wet as in I'm soaked from the saw splash after cutting down the rounds all day. It's wet after YEARS of sitting, its stringy, its crotchy, its big and .... it's what I have available.

SO... I can either b*&ch; about the problem or I can be the solution. I want to build the next generation of my splitter to be a solution. I'd like to run at least a double split (crosshair type) wedge on my machine. MY question... I need a pump off the PTO, how much flow/psi should I look for? All pto pumps I've found operate at 2000 psi. 3000+ psi would be a bonus. My current ram is a 4" diameter and I'll use it till it breaks down. At which time I'll find a 5 or 6 inch.

My current setup is about a 15 ton splitter by calculation. This is the minimum I need and it doesn't quite get me by with a single split wedge.

Now if someone can point me in the right direction for a factory built model for $1500 or so, it's sold! But my guess is not. And my smiling bride would rather I spend time in the shop than in the house when the sun shines during the winter. So I need a project. We have a good marriage and I prefer to assist than desist.

So I'd welcome any suggestions.

 

[SolarAndWood]

Even your smallest tractor seems like a crazy amount of power for a splitter especially with a 4" cylinder. I've seen used TimberWolf 3 point splitters with pumps go for around $2K.

 

[ditchrider]

Thanks for the feedback. But that's my point. Tractors are intended to tug and propel machines. Hydraulics are a secondary thought. Thus, I need to propel a machine that busts up nasty old wet wood. If I can split using my smallest tractor at 700-1000 rpm all day, I still have about 45-50 hp to work with and use less fuel and my ears won't be ringing at the end of the day. BTW I like your quote in your signature. That's the size of wood stack I'm trying to get to. And I want to accomplish that in a couple of weekends.

Thanks again

 

[SolarAndWood]

The big PTO pumps are spendy and running at some fraction of 540 rpm are going to put out a fraction of what the same money put into a Honda clone and 16 gpm 2 stage pump would do. My 5 hp electric/16gpm splitter splits circles around around the 30 hp/8.7 gpm tractor splitter. The 3 point splitter has been moth balled for a few years because of the economics and ringing ears. Not sure you are going to be able to take advantage of the hp at such a low rpm unless you spend a lot of money or don't mind a slower splitter. The good side of that PTO pump is it is single stage as opposed to the two stage pumps found on the lower hp units. My pump doesn't kick down that often though and most of what I split is big and gnarly.

 

[MasterMech]

Upgrading the cylinder size on that unit will compound your problems with speed/tractor RPM. I would compare the GPM of your tractor hydraulics vs. the GPM available from a engine/pump combo. Unfortunately unless the engine is electric it won't do much for your ringing ears. My 9HP Robin on the Iron & Oak will run for 4+ hours on 1 gallon and the wedge is always moving. (I usually split with a partner.)

I think if you really want to go with a 4-way you're better off starting with a new splitter. The 4 inch cylinder is going to struggle with the 4-way unless it gets a serious pressure upgrade. Then again if most of your wood is already miserable to split, then going 4-way might be more trouble than it's worth. Multi-wedges work better in reasonably straight grained wood and they can make a lot of waste in really gnarly stuff.

 

[SolarAndWood]

Just a thought, my excavator gets around this with some kind of pressure sensing system. Runs at idle until a cylinder starts moving then kicks up to the throttle setpoint. It has a 4 cylinder 60 hp Isuzu in it with a 220 pound pump that I think is on the order of 50 gpm. Not sure how you would replicate that kind of system on a farm tractor for $1500 though.