Cylinder size and position for log splitter?

[JimS]

I have a 5" cylinder on a log splitter that I planned to run from my tractor (about 8 gpm as I remember). I am thinking I would be better off going to a 3.5" or 4". I don't have to be able to split EVERYTHING. If I have to toss a really tough one aside now and then I think that would be better than a slow cycle time. On the other hand I don't need a blazing fast cycle time either. Want to keep my fingers. Anyone have a link to speed and force calculations?

What's a reasonable compromise? I could go with a regen valve but the 5" cylinder (2" rod) will still be slow with 8 gpm.

My other questions are about height of cylinder pins above the main beam. Right now they are about 3" up on a 8" pusher (wedge is also 8"). Should the pin be centered at 4"? And how long should the guide for the ram be? The one I have needs to be redone. How long is reasonable to keep it from twisting and jamming?

 

[glastron23]

Hi Jim... use this site Hydraulic Cylinder  Speed Calculator
as far as the ram guide we use 14 inches, it's long enough to stop twisting and still short enough not to cause extra drag, Jim

 

[lostcause]

i'm powering a 3 1/2" x 18" ram with my jd 770 (5.6gpm) and the cycle time is fine for a one man operation. i cut to 16", so i had no need to use a 24" ram - you just spend more time waiting for it to take up the slack before it hits the log. i do need to run around 1500rpm to get the speed i like - at idle it is too slow. your 5" cylinder will take about 2x as much fluid to move at the same speed as my 3 1/2", so it probably will be a little on the slow side. mine is not a speed demon, but i think it's certainly acceptable. a 4" would probably be a little better with your hydraulics.

my splitter is a 3 1/2 x 18 cylinder on a 4" W4 beam. the guide is an L6x4x3/4 with the 6" leg as the guide along the beam. so far it seems fine. i do, however, keep the cylinder as close as possible to the beam, to eliminate the beam bending. i only used the L6x4 angle because it was available at the tie. i ag goig to lengthen that 4" leg at some point, so i can split more than one piece at once.