Wood spitter question

Sun Jun 26, 2011 6:25 am

Hi Y'all
I'm building my third woodsplitter and have a question about the speed of my ram. I have a 8hp Honda this time (the others were 5.5) with a 16 G/pm two stage pump. I would like to have a 4.5 or 5in cylinder and 2 or 2.5 in ram. The others I have built seemed to be too slow for me. Is there a better combination pump/cylinder/ram that I can use that would give me just as much torque (25T) with more speed? The whole idea behind a two stage pump is the speed not under pressure and the speed when it is under load isn't it? Would I loose torque if I went with just a single speed pump? The store that I will be getting this pump from has pumps with 5000psi that would fit with #10 port holes. The pump made for splitters(two stage ) has 3000 with a #6 or 8

Any advice would be great.
Thanks Guy's

Re: Wood spitter question

Sun Jun 26, 2011 8:34 am

Using NorthernTool's catalog as a source.

Increasing log splitter speed. Haldex 2 stage hydraulic pumps - 22 gpm and 28 gpm pumps are available. Either pump should operate the log splitter's cylinder faster than the 16 gpm pump.

The 5000 psi pump - check the gpm. You may find that gpm for the single stage high pressure hydraulic gear pumps are the same or lower than your current 16 gpm 2 stage pump.

Re: Wood spitter question

Sun Jun 26, 2011 11:43 am

Yes , you are right. The psi's are lower. So, looking some more, its a haldex that I am looking at also but if I went with a say 22gal/m pump, it would requirer a 16hp min pump. The biggest pump I can use for my hp (8) is the 16g/m
If I had a 4 or 4.5 in cylinder, and a 2.25 inch ram, would that give me enough speed without losing too much torque

Re: Wood spitter question

Sun Jun 26, 2011 3:00 pm

I'm really not going to be able to directly answer your questions. You will have to do a number of math problems.

Major limiting factor is the 8 hp engine. Horsepower required = flow rate (GPM), times system pressure (PSI), divided by 1744, times pump efficiency. Source - NorthernTool. No use purchasing a pump larger than the 8 hp engine is capable of handling.

To gain cycle speed you could go with a smaller diameter cylinder/piston. But if you do that you loose torque/tonage.

Next option to gain cycle speed is to operate the engine at 3600 rpms, the suggested maximum rpms for the two stage pumps.

My current home made log splitter has a 2 stage pump, 4" cylinder with 30" stroke, and powered by a 10 hp Kohler engine. Most of the time I operate the log splitter with the engine at low idle to low mid range. The unloaded cycle - out and back is around 45 seconds. Being an old guy, the unloaded movement time doesn't give me much of a break.

Re: Wood spitter question

Sun Jun 26, 2011 3:19 pm

Ok, On the previous one I had built, I used a 3.5" cylinder and it had a 2" ram. The speed was very good but the torque wasn't there. I changed it out for a 5 in with a 2" ram. It was considerably slower. Too slow. So I'm thinking if I used a 4.5 with a 2.25 ram that it should be ok. Like you said, I think that the only way to get more speed is too rev up the motor to 3600.

Re: Wood spitter question

Sun Jun 26, 2011 3:19 pm

Here is the website for Baum Hydraulics.
http://www.baumhydraulics.com/home.php? ... d08064ab6c
Call them and talk to the rep for your area. Not only will he give you good advice, but you will get quite a bit better price than shows on the website. The one that covers my area is also an antique machinery fan (mainly Cat dozers), but is interested in all the old stuff, so be prepared.

Re: Wood spitter question

Sun Jun 26, 2011 7:09 pm

Running some numbers

Cyl dia. = bore

3.5" bore = 9.6 sq in X 24" stroke = 230 cu in. 9.6 sq in X 3000 psi = 28800 psi or 14.4 ton

5.0" bore = 19.93 sq in X 24" stroke = 471.12 cu in. 19.92 sq in X 3000 psi = 58890 psi or 29.44 ton

4.5"bore = 15.9 sq in x 27" stroke = 429.41 cu in. 15.9 sq in X 3000 psi = 47700 psi or 23.85 ton

Providing I didn't make any math errors. The 4.5" cylinder will be just a bit faster than the 5" cylinder.

4.0" bore = 12.57 sq in x 24" stroke = 301.5 cu in. 12.566 sq in X 3000 psi = 37698 psi or 18.849 ton.

Edit: 231 cu in. in one gallon. You could use the cylinder's capacity in cubic inches and the pumps maximum gallons per minute at recommended maximum rpms to get a general idea of the unloaded cycle time.