How big a splitter should I make?

[moosetrek]

OK I've decided, since we have some elm this winter, that splitting by hand is useful, builds character, and works well on pine. But since my welder is feeling neglected, and the cure for chilly fall evenings is often found in the shop, that I need to build a splitter. So here's what I'm thinging/wondering:
1) How many HP for the motor? I'm assuming a minimum 4" cylinder with about 20" or more of throw. Would 12-15 HP from a lawn tractor do it, or do I need more like a 4-cyl or diesel industrial?
2) What size pump and reservoir works well?
3) What do I need for a frame? I'm looking at some I-beam, either 8" or 12", either one is available
4) What's the best for the point? I've seen some that are just 1/2" plate with an edge, others are a lot wider.

Ideas: Buy in town has an old Jacobsen hydraulic lawnmower. Probably about 12-15 HP, hydraulic drive to the wheels and the mowers (3 of them). I can get it for $150, motor runs and no hydraulic leaks. Would this be a good beginning? I can keep the mower on the frame, and use the existing forward/back controls for the hydraulics.

Mostly stationary, I'll add 16" wheels and tires and a hitch to pull it in the back woods as needed. Probably add a log lift, if the motor will do it?

Thoughts/suggestions welcome, thanks!

 

[computeruser]

Building the splitter on a lawn tractor chassis is a nifty idea. A buddy did that, though he scrapped the original engine. Never did get it powered up, but it would be fun enough to do.

As for specs, if you're into elm on a regular basis, aim for a 4.5" or 5" cylinder rated at 3000psi and running fairly close to it. A 2-stage pump will be your best choice, 16 or 22gpm for the 4.5" cylinder, and 22or 28gpm for the 5" cylinder, so you can have nice quick cycle times. As for engine, .5hp per GPM on your pump is a good guide for sizing your engine, so there is really no need whatsoever for a 4-cylinder or diesel engine. Aim to have at least as many gallons in your reservoir as you have HP (assuming .5hp per GPM), though more is certainly better for cooling and whatnot.

Base cylinder travel on your anticipated wood size. If you're splitting 16" wood, a 18'20" cylinder is plenty. If you split 36" wood for a boiler, size accordingly.

Wedge design can go different ways. Skinny wedges slice the wood, wider ones pop the wood apart. I think that a prefabricated wedge or a welded triangle would be easiest to fabricate for a wedge-on-beam setup, unless you opt to have a wedge on the cylinder instead of on the beam; this is a personal preference thing, depending on how you like to handle your firewood as you split it.

 

['bert]

I suggest you price every part out before you begin to build your splitter. There is very little if any to be saved by building it yourself. The reason I built my own was that I originally ran it off the tractor, had access to free steel, had some spare hydro hose, and a free cylinder. Also I was looking for a project to learn on with my new MIG.

If you have to buy everything, the economics do not work out. If you are doing it to have a project, that is a different story.

 

[Tony H]

ABurner makes a good point one of my pals built one he had the I beam and a 10hp motor and still spent about 500 on it. I found a older used one for 450.00 that has a newer 8hp motor and one of the beam reservoirs must hold 2 or more gallons of fluid. Elm is a good reason to get a splitter . One thing to consider is the height of the splitting surface the one I have they made a bit low to make is easier to get big logs up but it gets to your back before long and the too high ones are tough to lift a log up to. What I wish I had is a tall sized beam and a log lift to pick up the big stuff also would like to have the option to split vertical

 

[moosetrek]

Alberta,

I'm assuming your reference to costs is for new parts? From what I can tell you're right, it's cheaper to buy one. But I have access to a couple cheap cylinders, on 4" X 20" for $75", one a 6" X 35" (overkill). The hydraulic pump on the lawn tractor ($200 complete) should work for hydraulics, the motor is good, and I have several 8' I-beams about $30 ea. I've already got some tires, I can pick up a trailer house axle cheap, and a little scrap steel around the place. I figure about $4-500 into it total for a decent splitter. I can't buy one that cheap that doesn't need work, and besides; I love the smell of melting steel in the morning

 

[Dune]

Here is my input FWIW. Go with the larger I beam, wieght doesn't matter, extra strenght is always good. Go with the bigger piston, 4" is marginal, especialy if you ever put a four way on and want to split big rounds of knarly stuff. 4" would work most of the time, but why limit yourself? Too much is always enough.
Do not put the wedge on the piston, makes it harder to add a four way. Build a single wedge, and make a slip on four way that drops over the single wedge. You will want both options.
Before you commit to the riding mower, find out the operating pressure of the hydraulic pump. You need 2500 P.S.I. and it may not have that.
You will have enough juice for a log lift either way, you only need a two inch piston for it, and it will not be in use at the same time as the big piston.
I always figure tank size based on pump volume: one gallon of tank for every gallon per minute of pump. This gives you one minute to notice a broken house and shut the motor off before you lunch the pump, and provides better cooling for the oil.
Here is my formula for horsepower, it is simplified a bit, but still works; 1 hp per gallon per minute @ 1500 P.S.I. Extrapolate from there.
Just so you know, I have designed and installed over 100 hydraulic systems, including building the tanks, mounting the pumps and building the equipment they run.

 

['bert]

Yes my reference is to the cost of new parts. If you have some access to used material then it's a different story (that was my case). Make sure the lawnmower pump does generate the required PSI as mentioned. Most importantly, do you have someone to hold your beer while your welding? :coolsmile: