Just some real-world info for comparison.
I have a splitter with a 4x24" cylinder, a 16 GPM 2-stage pump, and an
8 HP engine.
Extend time is about 7 seconds, retract about 5.5. Definitely go
for a smaller cylinder. This splitter goes through everything that
I can put on it. It has split some really knarly crotches w/o
complaint.
The calculations that I ran before putting this pump on (the pump that
came on it was a lower GPM pump) said it should extend if 5 seconds,
so you'll probably want to add like 25% to your time calculations.
I have a Kubota B7100 that has 16HP engine/12HP PTO. I was
looking at tractor-powerd 3PH splitters, but my hydraulic pump only
provides 3.3GPM @ 1700 PSI. That wasn't going to give good
performance. Then, I started looking at PTO pumps. All PTO pumps out there are single stage. An 8 GPM pump would have been the best I could do. That would have given me a 15 second extend, 25 second full cycle (extend and retract). That was too slow.
For info on what a two stage pump is, look here:
Hydraulics
Q: What is the difference between a one-stage pump and a two-stage pump?
A: A one-stage, or single-stage, pump has only one maximum pressure and one flow rate. Single-stage pumps are typically attached to the crankshaft or PTO shaft on a farm tractor or large industrial engine. Applications for a single stage pump include backhoes and manure loaders.
Two-stage pumps are typically mounted to small gas or diesel engines. A two-stage pump will first produce high volumes of fluid, moving the cylinder in and out quickly. When the pump receives resistance, a second set of gears will produce high pressures for lifting or splitting. However, the volume of fluid will drop considerably during this stage.
This mechanism has many practical applications. For example, in log splitters equipped with a two-stage pump, in stage one, the rod travels faster up the cradle until the rod starts to split the wood. At that point, the speed slows but the force increases.
So, I looked into getting a gearbox to increase 540 or 850 RPM (the two speeds of my PTO) to 3600 to drive a normal two-stage pump. These gearboxes start around $300 (as do the PTO pumps). With 12 PTO HP available, I could drive a 22 or 28 GPM pump (which are also around $300-$400), so i would have been looking about $600-$700 just for a pump and gear box. Then, I'd still need a tank and valve.
I ended up just buying a used 24 ton splitter for $700. It has an 8HP engine, and had an 11 GPM pump (which I upgraded to a 16 GPM pump from Surplus Center for $140).
Now that I'm using it, I am glad that I don't have a tractor-powered splitter, as I use the tractor to move the firewood to and from the splitter, and would need to unhook the splitter each time. Also, I use a 3PH carry-all to move the finished pallets of firewood. I would be switching it on and off to put the 3PH splitter on and off.
There are a lot of threads here on TBN about stand-alone vs. tractor mounted splitters.
, Typing in all capital letters is considered YELLING on the forums and it very hard to read.
