High speed hydraulic wood splitter
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What you are suggesting is not likely. 16 to 18 HP motors driving a 22 to 28 CFM pump is fast enough for most splitters that can be towed behind a ordinary pickup. Your limit if you have a factory built splitter is your ram and hoses. You need at least a 3/4'' hose system to run a 22 CFM pump. I like a 18 HP motor running a 28 CFM pump. I have several set ups. My current project is a 5 1/2 '' ram that only had 1/2'' fittings so cut off the old fittings for a 1'' set up. Surplus Center had all the hoses that I needed. Now trying to get the log lift just right. If you have a 4'' ram as I have seen it is too fast for me its dangerous. Not interested in loosing any of my fingers or do I want some one else to. Thanks
Modifying a old splitter to do what you are wanting is a waste of time and money. Can it be done? Sure, but by the time you rebuild and replace all the parts, you could have built something much better. Anytime you start trying to pump more oil faster it is going to require more engine hp to get the job done. I don't know of anybody that makes a 3 stage pump that just bolts up to a motor, maybe they do and I just haven't seen one. This leaves you with a couple other options. Converting your hyd system to a close center system and using variable displacement, load sensing pumps, or staying with a open center system and installing several smaller pumps, along with the dump valves. to make your hydraulic system a true hi/low system. Both options will require a larger engine, larger hyd tanks, as well as oil coolers and a bigger control valve. All for a pretty large investment. Probably the most cost effective way to speed up a old splitter is to simply replace the cyl with one that uses a larger dia rod. You wouldn't lose any splitting power, and would gain your cycle speed on the return stroke of the cyl. Adding a dump valve for returning oil might be necessary, but is still way cheaper than completely converting a old machine or building a new machine from scratch.
Nate as Mudd suggested what you want to do is not practical. I have never heard of any effective pump that can dramatically speed up your operation. Larger motor, larger pump, larger hoses and likely a different cylinder is probably the only answer. This question comes up often. Motor $400, pump $250, hoses $100-$200, control valve $150, and some minor modifications. If you have a small cylinder and you put a 28 cfm pump behind it it will likely be too fast. Maybe a 22 cfm pump with a 12 to 15 HP motor might be a compromise. Thanks
22 cfm is not practical even on large construction equipment as that is 165 gal per minute. 
Most log splitters are in the 10 - 16 GPM range.
One way to get faster extend speeds would be to use regeneration where you take the return oil from the rod end of the cylinder and combine it with the pump flow to get faster cylinder speeds. The disadvantage to this is that that your working area of the cylinder is reduced to the area of the rod so your force is greatly reduced. Therefore you need a valve where you can shift back into the normal power position and use the full area for full splitting power. There are valves out there that offer this as a 4th position that would work very well and give you faster speeds without adding pump flow.
Most log splitters are in the 10 - 16 GPM range. One way to get faster extend speeds would be to use regeneration where you take the return oil from the rod end of the cylinder and combine it with the pump flow to get faster cylinder speeds. The disadvantage to this is that that your working area of the cylinder is reduced to the area of the rod so your force is greatly reduced. Therefore you need a valve where you can shift back into the normal power position and use the full area for full splitting power. There are valves out there that offer this as a 4th position that would work very well and give you faster speeds without adding pump flow.
homemade
Certified Chainsaw Tester
There are several ways to get more “speed” out of a hydraulic system. And each one comes with a drawback.
1) Smaller diameter ram. But you loose splitting force.
2) higher flow gpm pump. Need more horsepower or a lower relief pressure and you loose splitting force. And once you go beyond 25 gpm, most hydraulic appliances need upgrading to Handle the flow. Valves and filters and hoses and such.
There is also a fact of wood input and output. Can that keep up currently?
I run a 4” ram with a 22gpm pump on a 11 hp engine and a relief set to 2000psi. That is faster the three people working (me and two old unskilled helpers) can keep up to. I put a pressure gauge on my rig just to see what I was getting. Maybe touch 2000psi once a cord and 80% of the time I’m below 1000psi. My next step would be a smaller ram but I can’t feed and stack it to keep up to the splitter.
1) Smaller diameter ram. But you loose splitting force.
2) higher flow gpm pump. Need more horsepower or a lower relief pressure and you loose splitting force. And once you go beyond 25 gpm, most hydraulic appliances need upgrading to Handle the flow. Valves and filters and hoses and such.
There is also a fact of wood input and output. Can that keep up currently?
I run a 4” ram with a 22gpm pump on a 11 hp engine and a relief set to 2000psi. That is faster the three people working (me and two old unskilled helpers) can keep up to. I put a pressure gauge on my rig just to see what I was getting. Maybe touch 2000psi once a cord and 80% of the time I’m below 1000psi. My next step would be a smaller ram but I can’t feed and stack it to keep up to the splitter.
Just to provide an example of how to accomplish what you want to do, but is by no means a suggestion to actually try this.
Not knowing anything about what you already have as a splitter or parts for a splitter I will throw this out there. Determine the amount of splitter force you desire first. This will help determine the size cyl you will want to use. I find a 5 in dia bore cyl will pretty much split anything I care to try. 5in cyl's commonly are found with 2in and 2.5 in dia rods, but 3in rods are available and even larger rods can be had if custom ordered. The choice really depends on how deep your pockets are. I would seek out a cyl with a 3in rod as that size would sort of fit in between efficiency and economy, but I wouldn't hesitate to use a 2.5in rod size if that was all I could find or afford. Any math I use from this point will be based on a 5in bore x 3in shaft and 24in stroke.
A common 28gpm 2 stage pump is easy to find and will give the chosen 5in cyl a cycle time of 7.2 sec of no load speed and provide about 29.5 tons of splitting force. The hp required for the pump is min of 16 hp. The pump produces 28gpm of flow at 400-900psi and only 7gpm at 3000 psi. In the high flow mode and 900psi the cyl will produce about 8.5 tons of force. I find this is enough force for the small straight grained wood and my pump doesn't even shift into the low flow high pressure mode. I also have found the 7.2 sec cycle time to be closer to 10sec than 7sec. Still the speed seems plenty fast enough for me. Once my pump does kick into high pressure low flow cycle times do increase by a lot, altho I haven't actually timed it. I find myself waiting on the machine, so I can understand the desire to have that third stage somewhere in between the 7gpm and the 28gpm.
This is where things start getting interesting. Nobody I know of makes a 3 stage pump. To combine parts to come up with a 3 stage setup brings in a easily solvable problem, yet it does come at a cost. I am not going to assume a person is working on a old machine reusing parts already there simply because their max pump flow and engine hp are already limited, and the cost of doing the conversion isn't going to be cost effective for the amount of speed that they would gain. Instead I suggest selling the existing engine pump combo and upsizing everything, or starting from scratch. I would look for a triple pump setup sized around 12gpm each section. This would give you a combine flow of 35gpm. I would install a unloader valve between the first and second pump outlet and a second unloader valve between the 2nd and third pump section. I would set the first unloader valve bypass pressure at 1000psi. This would give your 5in cyl about 9.5 tons of splitting force in the 36gpm high flow, about 1 ton more than you had with your 28gpm two stage pump. The second unloader valve I would set at 2000psi, this would give you about 19.5 tons of splitting force at 24gpm pump flow, This would probably be enough force to split 90% of any wood you encounter. The third pump I would set the relief pressure on the main relief at 3000psi and you would have 29.5 tons of force @ 12gpm for the really hard wood to split. This would be equal to your current setup with the 28gpm two stage pump at 40% more pump flow/speed. To pull the pumps you would have to step up to about a 25hp engine. No load Cycle times would drop to 5.2 sec instead of the 7.2 sec. The actual cycle time will depend on just how much force is needed to complete a split. One should see a big difference even in the high pressure times and if the wood splits in the low or middle pressure ranges, cycle time would be blazing fast.
One of the things you would probably have to give up is the detent retract or autocycle of your control valve. I haven't seen any autocycle or detent return valves rated for more than 25gpm. You would also more than likely have to add a dump valve to the return stroke of the cyl as the return flow will probably be closer to 70gpm, (I didn't do the math), than the 36gpm your pumps produce. You would want to make sure your valve and cyl ports are at least 3/4 dia and 1in would be much better. You will also need a much larger oil tank and might as well add a cooler. You will also need to make sure your return oil filter is large enough to handle the returning oil flow. I also wouldn't built the hyd system without a suction filter. Triple section pumps get expensive to replace if a piece of shaft seal gets sucked into the pumps. Another expense would be all the extra hoses and fitting to plumb in the unloader valves an dump valves. I would also install at least 3 pressure gauges, one for each unloader valve and one for the main relief. You will need the gauges when you start setting the pressures on the unloader and relief valves.
Mudd pretty much has it all above. Here are a couple additional options:
1. Regeneration circuit on the cylinder for fast extend. Then two stage on extend to split, and full two stages on return. Unless you have a very large rod, this would get awfully fast though, and take some good math and proper settings. Would also take all the larger hoses and components noted above to handle the high flows.
2. Adding a separate 3 inch or 4 inch cylinder with an unloading and recirculation circuit to the big cylinder, for faster travel until it hits a load. This is commonly done on big hydraulic forming presses on a giant scale, but the concept is similar.
3. Leave it alone and make a totally second separate splitter. This is what I would do. Split the big stuff as needed, and anything say 16 inches or under with the fast machine.
I have a post here somewhere in tyhe archives about my ‘Bantam’ portable splitter. Just ran it about 5 more hours on Sunday splitting oak at a charity event. It is a 3 inch cylinder, 5 hp engine, 13/3 gpm pump. 19 inch stroke is 3 seconds out, and 2.8 seconds back. Splits up to about 12 inches through, and bigger stuff take 1/3 off the sides. To keep the wedge running continuously takes 3 people, although 4 would be better for 100% cycling. Two people, rolling rounds off the trailer, can do one full cord per hour.
It is NOT for big elm or anything like that, but was designed for speed in log loads of oak.
Then use the big slower one for the hard pile. If you are a tree service, this is not the right plan of course.
“If your gear is never too small, it is always too big” My goal is maximum wood done in minimum time, and leaving the big stuff, that I cannot lift anyway, doesn’t matter to my ego.
Again, your application may be totally different, but I would either:
-have two machines
- or sell this one as is and buy a bigger one to start with. Buying a 28 gpm, 5 inch bore machine, then putting a 4 inch cylinder onto it would be the fastest and most economical way of getting tyhere. All the components would be sized for flows. Changing cylinders would give you a quick (5/4)^2 or about 50% speed increase. ( and decreased force of course)
-sell this one and build a bigger one from scratch design.
I would not do all the upgrades to the existing. I think you would end up replacing every major high dollar part and still end up with a compromised performance in the end.
1. Regeneration circuit on the cylinder for fast extend. Then two stage on extend to split, and full two stages on return. Unless you have a very large rod, this would get awfully fast though, and take some good math and proper settings. Would also take all the larger hoses and components noted above to handle the high flows.
2. Adding a separate 3 inch or 4 inch cylinder with an unloading and recirculation circuit to the big cylinder, for faster travel until it hits a load. This is commonly done on big hydraulic forming presses on a giant scale, but the concept is similar.
3. Leave it alone and make a totally second separate splitter. This is what I would do. Split the big stuff as needed, and anything say 16 inches or under with the fast machine.
I have a post here somewhere in tyhe archives about my ‘Bantam’ portable splitter. Just ran it about 5 more hours on Sunday splitting oak at a charity event. It is a 3 inch cylinder, 5 hp engine, 13/3 gpm pump. 19 inch stroke is 3 seconds out, and 2.8 seconds back. Splits up to about 12 inches through, and bigger stuff take 1/3 off the sides. To keep the wedge running continuously takes 3 people, although 4 would be better for 100% cycling. Two people, rolling rounds off the trailer, can do one full cord per hour.
It is NOT for big elm or anything like that, but was designed for speed in log loads of oak.
Then use the big slower one for the hard pile. If you are a tree service, this is not the right plan of course.
“If your gear is never too small, it is always too big” My goal is maximum wood done in minimum time, and leaving the big stuff, that I cannot lift anyway, doesn’t matter to my ego.
Again, your application may be totally different, but I would either:
-have two machines
- or sell this one as is and buy a bigger one to start with. Buying a 28 gpm, 5 inch bore machine, then putting a 4 inch cylinder onto it would be the fastest and most economical way of getting tyhere. All the components would be sized for flows. Changing cylinders would give you a quick (5/4)^2 or about 50% speed increase. ( and decreased force of course)
-sell this one and build a bigger one from scratch design.
I would not do all the upgrades to the existing. I think you would end up replacing every major high dollar part and still end up with a compromised performance in the end.
Instead of using regeneration, we could plumb in an accumulator. Naw, never mind, Those things scare me ever since I got ran over by a runaway TRM that had a accumulator plumbed into its travel circuit. Machine was un-occupied and just took off.
Unless you are wanting this for a processor I see no need or desire to work any harder/faster than my splitter does.
I have a 22 gpm pump, 11 hp Predator engine, 4" x 30" stroke cylinder (I cut my wood 24") and it's plenty fast enough for me.
I have a 22 gpm pump, 11 hp Predator engine, 4" x 30" stroke cylinder (I cut my wood 24") and it's plenty fast enough for me.
I agree 100%. I have done a full cord in 15min with 4 helpers with my splitter. I don't always have 4 extra sets of hands to keep the splitter fed. Once I stage my wood for spitting, I can do a cord in about a hr by myself. I was burning about 4 cords per winter, so about 4 hrs to split all my wood for the season. I seldom spend more than 30min at the wood pile at a time. I buck wood when testing out a saw, I might split a little when the rounds start getting in the way of mowing. Do a little here and there and pretty soon my wood work is done. I guess that's why I haven't finished my processor I was building and I haven't built a splitter like I described. I don't need anything that fast. Doesn't mean it cant be done tho for someone that actually needs a splitter with that kind of speed.
homemade
Certified Chainsaw Tester
What about a super split. No one mention inertia drive yet.
Because no one asked how to put a 3 stage pump on a supersplit.
I have never even seen a super split or any other brand of inertia splitter, so I shouldn't commit on how well one does or doesn't work. Since I haven't done anything all day today I will anyways. From videos the super split seems very fast. I do question its performance on really tuff to split stuff. The big stuff, it seems folks have to strike it several times to get the wood to split. That super fast stroke is like swinging a go-devil. You hit the wood hard enough and it splits, if it doesn't split, you hit it again and again until it does split.
With a hydraulic, you can still run across wood that doesn't want to split, but not often. I suspect technique similar to splitting with a maul would be helpful with a inertia type splitter, meaning splitting around the edges instead of wacking away at the center. I often roll a big round to split the edges with my hydraulic splitter, altho for different reasons, so I guess the same things that works using a maul helps a hydraulic splitter, as well as the inertia splitter. The reason I said for different reasons is that my splitter doesn't seem to care what kind of fork or knot its cutting thru, it just powers on thru. I find cutting the edges to be helpful when working with over size rounds. I can let the large part of the round rest against my body as I peel small pieces off to fall on the ground and then simply just roll a little more of the round back on the beam for more splits. Cutting the big round in half the first pass of the splitter means letting one half fall on the ground. Yea, I know, I should build a splitting table for the end of my beam. 
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Cycle time might determine the ram speed but it is only one of several factors that you need to look at. I assume you are looking for the most split firewood in the quickest time. I built a 36" splitter with 4 way adjustable wedge with an auto cycle valve. I also use conveyors to move the splits away. There are many ways to speed up a firewood operation, almost all of them cost money. There is also the tree falling, hauling, storing side too. If you want a fast splitter then look at these treasures. http://www.eastonmadewoodsplitters.com/
Put a 2-cycle on it, and crank up the revs...
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