Log splitter build

[Power2ll]

I have been off here a while but I am back and I have a new project I have wanted to build for awhile. I have taken some pics as I build. This thing is going to be a beast. I am tring to figure which pump to use on this thing. I have a 12hp Kubota diesel and a 37 ton ram and am thinking of using a 16gpm pump does anyone have any feed back

 

[DJ54]

The only suggestion I would make, no matter what gpm pump you decide on, would be to get a two stage pump. It'll make it a whole lot easier on your engine, getting through the tough ones.

 

[ajmaxham]

I just checked on the Dalton Hydraulic site - 16 gpm log splitter pump needs a 8 hp gas engine - 22 gpm log splitter pump needs a 12 hp gas engine - if the Kubota diesel has the same or beter ft lb torque value at 3600 rpm as a gas engine you can use the 22 gpm log splitter pump.

 

[muddstopper]

If you have a true 37ton cylinder, (6in boreX3000psi) I think your ram speed is going to be a little slow with the pump you have chosen. A 6in cylinder with a 24in stroke will take about 12 sec to fully extend. Rod dia will determine the retraction speed, but with a 3in rod, you can figure about a 8 sec retraction time, or about 20sec full cycle. A 22gpm pump using the same cyl will give you about a 8sec extention speed and a retraction of 6 sec, 14 sec cycle.
A single stage pump at 22gpmX3000psi will take a 45hp engine to pull it. I would assume you are planning a 2 stage pump which only makes 22gpm at around 800psi in the high flow mode, and this would make your 12hp engine marginable, but would work.

If your cylinder is a 5in bore, it will take around 3800psi to get a true 37 ton of splitting force. With a single stage pump, it would take 42 hp to pull it. I dont think any of the 2 stage wood splitter pumps are rated for 3800psi, at least i havent seen any rated that high. A 5inX3000psi is still a 29ton splitter and is what I currently have on my machine. I also use a 6way wedge on large dia oaks with no problems. The 5in x 2inx 24in stroke cylinder using the 22gpm pump will give you around a 10sec cycle time and within the limits of your engine, (barely). 16gpm pump = 14sec cycle. These cycle speeds dont take into account the time the pump spends in the low flow high pressure mode so actual cycle times will be somewhat slower. My current slitter uses the 28gpm 2 stage pump, 5x2x24 in cyl and a 25hp kholer engine and actual cycle times are about 12sec.

 

[Oliver1655]

Muddstopper has some good info.

OP - It is better to give measurements on the cylinder & it's ram than tonnage. The cylinder bore, ram diameter, & psi of circuit will all effect the tonnage. Manufacture's are notorious for over rating the tonnage of splitters.

Most folks who build a splitter would like a cycle time of < 10 sec.

I don't know what you are planning to split, but I have a 4" cylinder with 1.75" dia. ram with the pressure relieve set at 2,500 psi & get a cycle time of 8.8 sec which provides 15.7 tons. I use a 21" high 4-way wedge 95% of the time & can split/cut through elm, hedge, ... without problems. Key point is to have a sharp narrow wedge so you can cut through gnarly pieces instead of having to tear them apart. I rarely will split anything larger than 24". If the round is larger I will noodle it in half or quarters to make it easier to handle.

Your 12 hp diesel engine will be able to handle a 22 gpm 2stage pump. Make sure you are using 3/4" lines.

 

[FarmWrench]

I don't split much wood.
I do think about building a better splitter more than I run one.

Speed and safety with capacity should be your objective. I know lots of stubby fingers that were cut off by slow splitters. People try to make up time and think there is more time to move to a safe spot when they get bit. The majority of wood splits with out difficulty, getting the most stubborn piece split is false economy. If having the piece stuck on a wedge is the reason to build better, solve getting OFF the wedge not going THROUGH the piece.
If you really want to go with a big slow cylinder then use a small box blade and a hook to hold the piece to the ram. Otherwise start thinking fast cycle speed.

 

[Texasmark]

I have a 4 x 24 cylinder I bought from ASC and a homemade ram. I toyed around with the cutter and through 4 iterations I got what I want: The blade 8" tall, is as sharp as my hand grinder can make it, and is made from 3/8" steel stock. Approximately 3 inches beyond the point and welded to it, is the wedge which flares about 20 degrees in both directions. This setup provides the maximum #/square inch initially to get the blade into the wood and once it's started the flare to force the log apart.

I had been running it with my tractor but to offset cabin fever this winter I had an old riding lawn mower sitting around with a shot deck and decided to make a pump driver out of it hoping to be more convenient than the tractor and it surely turned out that way.

The engine is a 15 hp Kohler 1:1 V belt driving the 16 gpm 2 stage pump (8 hp drive requirement @ 3600 rpm stated) from Northern Tool where I also purchased the "log splitter" control valve, Lovejoy drive sockets and mounting bracket for the pump, all to allow me to V belt drive the pump. In surfing the www I found a hydraulic site where I learned a few things about log splitter hydraulics which helped in the design.

First thing I learned was to keep the runs short. Outlet of the pump is 1/2" so the pressure line to the controller is 1/2" and about 18" long. Return from the pump is 3/4", about 24" and routes to the filter and 2.8 gallon oil reservoir. Also the site said that making the return large helps your cylinder retraction time. Lines to the cylinder from the control are 1/2" x 5' each, reason being I wanted to sit between the splitter and the drive unit. Unloaded cycle time is 7 sec out and 6 back with the Kohler running at the notch in the throttle plate which should be right at 3600 rpm. I am really pleased with that as my tractor was really slow....partly because I had very long 1/2" lines between it and the cylinder, plus the pump was only about 8 gpm.

Yesterday I was splitting some 24" trunks from a tree I cut back in December; wood is Hackberry, kind of green and stringy like Water Elm. I deliberately made my splitter close to the ground so I could roll logs to it and minimize my lifting, in addition to being able to work large pieces alone, as I was doing yesterday. On these big guys, I used automotive ramps to roll them up and onto the beam. I could hold them in place with one hand and reach over to the mower to get to the control handle for the split.

The ram zips right up to the log at a nice clip as stated and as soon as the blade contacts the log the second stage of the pump immediately kicks in. You can hear the engine load up somewhat with the new load but the second stage (high pressure, slow speed) only runs for a couple of seconds, just long enough to get the knife edge embedded in the log and then the pump reverts back to low pressure high speed, and the ram moves out again and pushes the split log off the end.

In running the numbers it says that my setup is capable of only 15T of force. But the name of the game isn't force per se, it's force per unit area. That's why I have the sharp edge on the blade and keep the wedge part back from the tip giving time for the blade to get embedded in the wood before you attempt to split it.

It's a pain, but if you are really interested I can send you some pics of my setup.

HTH,
Mark

 

[J_J]

You are probably closer to 16 ton.

A sharp wedge does help and you have plenty of HP.

Any pictures.

 

[Texasmark]

Ok. It was supposed to get to 74 today. I walk outside, it rained last night, the wind is out of the N and no way will it be 74. So I got out the camera and took some picks of what I did yesterday waiting for supper.

With the site expander you can get a birds eye view of the pics for more detail.

I learned, somewhat into the project that the pump had to be turned CW looking at the shaft end and that it couldn't tolerate lateral loads....aka V belt drive. Since I wanted to use the pulley off the lawn mower that previously propelled it and it was turning CCW if I mounted the pump above the frame. Since I couldn't do that, I had to mount it where you see it and it required the drive (bracket and Lovejoy couplings) which added about $150 to the bill and then to get ground clearance since I had to mount the pump below was another $160 for the solid tires and wheels to raise the frame higher off the ground. However, the different type and style of wheel assys made it a dream to push around by hand.....original plan was to use the self propel function for moving about and drive the pump from the lower sheave that originally drove the mower deck......but it's fine as is.

The V belt was special as it had to drive the required hp. I did a lot of looking and found out that there are a lot of different considerations when one designs and produces V belts. This one just happened to be for a JD riding mower and cost about $27, but it can drive about 11hp and I only need 8 max.

The sump is the 2.8 gallon from NT also for about $70. Have no pump cavitation problems with this setup. Filter assy about $30 from NT. The inlet to the filter is 3/4" 300 psi hose (that's what the storebought units use in this spot) whereas the outlet is radiator hose. The "log splitter" valve from NT also was about $70. Add QD couplings and 1/2" hoses and you're pushing another $100.

Things kept adding up, but it's done, money spent and now I have a super splitter to use.

HTH,
Mark

 

[J_J]

In looking at your fittings use for the hyd, I would remove all the water pipe fittings as they are not rated for high pressure.

Otherwise looks like a nice clean build.