I don't have one handy, but I seem to remember that Northern Tool used to offer do it yourself log splitter plans. Obviously the splitter itself is a pretty simple device, but I don't know much about sizing the pump/cylinder or what pressures/flowrates would be needed. Now to throw something else into the mix-I'd like to build a splitter that would utilize a John Deere 110 tractor's PTO for power. The 110 is equipped with a horizontal shaft 10 HP Kohler engine, and has two pulleys fixed to the output shaft. One is connected by a belt to the rear axle/mowing deck, and the other is intended for PTO use. The only powered attachment I've seen for the front is a snowblower, which is belt driven. Anyway, I thought if you could design a frame that would mount to the front of the tractor that would hold the cylinder, pump, control valve, and tank, all that would be left would be to find the appropriate pulley/belt to connect the PTO pulley to the pump. I would think that 10 HP would be adequate for a splitter, and AFAIK the pulley is a direct drive off of the output shaft, so at 1:1 the pump could be driven at a maximum of 3500 RPM. I guess the biggest questions are as follows: What pressure/flowrate for the pump? What size cylinder? What kind of valve do I need?