# How to creat 40 tons of splitting force with 6-12 second cycle times on log splitter



## stihl2009 (Jan 26, 2011)

Hello everyone,I'm new to this site. I've done alot of looking to try and find the answer. However,it might just be easier to ask.. I'm looking to build a mega splitter. Something with a 6-12 second cycle time..6" Diameter 4"shaft cylinder....24 to 30" stroke on the hydraulic cylinder..However,I really cant seem to figure out what I would need to do to get a log splitter with this kind of splitting power to run a 6 to 12 second cycle time.. Single way pump I realize that would have a much faster cycle time but how big of a pump/motor would I need to generate 30 to 40 tons of splitting force at the 2250 psi.. Or what about the 2 stage pumps. Can I get a 8-14 second cycle time out of a 6" diameter with a much smaller motor and have the 30 to 40 ton of splitting force that I want...The reason I want something so powerful is because I intend to have my wedge screen about 22" wide and 22" tall with perfect triangles welded in for a "perfect piece of wood..No 6 or 8 ways..1 universal metal cage welded..I really want 30 to 40 ton splitting force(the firewood processors run through wood with that tonnage.. A similar wedge style would be the cord king 60 and 48 wedges.. I guess the question really is. If you wanted to build a splitter with 30 to 40 tons of splitting power with 6-12 second cycle times,how would you do it??/


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## stihl2009 (Jan 26, 2011)

Bump please!!


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## flewism (Jan 26, 2011)

Well, plug your numbers into these calculators, and tell us how your are going to get there. 

https://www.surpluscenter.com/techhelp/displetc.htm

https://www.surpluscenter.com/techhelp/cycalc.htm

look forward to seeing this monster.


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## stihl2009 (Jan 26, 2011)

Thank you very much..Only question,those calculations are using a single stage pump or a two stage pump? I assume its 2 stage pumps due to the fact that the calculation was for log splitters and 2 stage pumps were for log splitters but I dont know???? Again thank you very much. Now I have a starting point..


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## Cheese Whiz (Jan 26, 2011)

6" bore cylinder will get you to about 30 "real" tons with a 2250PSI pump, over 40 with a 3000psi pump.

It's gonna take 30gpm to do 12 second cycles on a 6x24 cylinder.

I suggest a single stage pump, and a 50+hp diesel powerplant, do ya have a tractor to PTO drive it?

A 2 stage pump is gonna spend a lot of time in "low" trying to do the splitting you describe, and a 28gpm 2 stage is only flowing somewhere around 5gpm when kicked down. LOOOOOOONG cycle time there.


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## flewism (Jan 26, 2011)

Those calculators are for single stage pumps. A two stage pump is actually two pumps within one. Both are running simultaneously under no or minimum pressure giving you high flow (speed). As pressure builds one pump kicks off reducing flow and building pressure. This is how an 8hp engine can run a 25 ton splitter.


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## Deereman76 (Jan 26, 2011)

I have always wanted to do this, but I do not make enough wood to bother. My Idea Solution is to use 2 Cylinders. Say, A 3 inch, and a 6 inch. During typical operation, the 6 inch is in a Bypass mode, meaning it is just sitting there, extending and retracting, being pushed by the 3 inch, with oil flowing freely from one end to the other. the 3 inch cylinder does the moving. When the splitting gets tough, you move a second lever that engages the 6 inch Cylinder. This gives you the speed of a 3 inch ram, with power of Both. In this case, (Both Cylinders, 2250 Psi) would be roughly 39 tons of force.

I want to stress that this works great in theory, but I have never tried it. If you do want to try it, I would be willing to help figure out the Hydraulic aspects of it....


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## Deereman76 (Jan 26, 2011)

TreeCo said:


> Seems to me I was reading about a valve that would send oil from in front of the piston to behind the piston to be added to what the pump in sending behind the piston. You may be able to use just a single six inch cylinder with such a valve. Under high load the oil from the front of the piston goes to tank.


 


Regeneration? Problem is, regeneration only works on the extend stroke, not on the retract... I Found this to be a good description of regeneration:

http://www.hwhcorp.com/ml37939.pdf

However, If you sourced a Cylinder with a 6 inch Bore, and, say a 5 Inch ram, the return cycle would be quick anyway. Perhaps Regeneration could be helpful....


So, a 30" long stroke, 6 inch bore Cylinder, with a 5 Inch Rod. 16 GPM Pump.

4.22 Seconds to retract
13.63 Seconds to extend with traditional plumbing
9.67 Seconds to extend with Regeneration. 

So, 4 seconds advantage to cycle time with regeneration.


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## stihl2009 (Jan 26, 2011)

Awesome guys.. I spent 2 days of searching google to find the answers that Ive been looking for..I create a thread and within 24 hrs I have some good information to go with,thank you very much.. I dont intend to power this log splitter pto. I have every intention of spending alittle more money to build a "commercial" splitter. As for tonage and pressure in the lines..I had mentioned 2250 psi. The reason Ive said this is when I was reading I found most people said this was ideal for safety reasons.. Should I bump the relief valves to 2500to3000psi to get that 40 tons of splitting force? I mean the pieces are only going to be 12" to 24" Pieces. I would assume a splitter of this size (45hp Kubota Diesel with a 6"cyclinder and a 28gpm pump would be everything and more that I would want..With a cycle time of 10 seconds and 1 helper to feed blocked logs..Im figuring I will easily run through 200 feet of 18to20" diamete blocks in less then 25 minutes..thats 4 to 6 cords an hour of splitting capabilites..I want the log splitter waiting on me,I dont want to wait on the log splitter


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## stihl2009 (Jan 26, 2011)

Alright.Again,thank you everyone.
So as of right now I'm thinking this would be the idea-

1-45 HP Kubota Diesel Motor
1-6" Diameter cylinder with a rod 3 to 4 inches.
1-28gpm single stage pump
1-Hydraulic reservoir? How many gallons recommended for this setup,more is better.Options to for cooling reservoir?
1-Welded 10-16 way wedge-I dont think I would need this on a cylinder due to its size(cylinder for up or down on the wedge to insure a perfect split everytime.
1-3500lb axel to hold this beast 
Going to build something so this splitter can mount to an elevator.
And the one other thing Im looking to do is instead of building a hydraulic lift.Going to build some sort of roller where the blocks continuosly roll to me to try and keep up with the production of this thing.. 
Does anyone think this splitter is unreasonable or anything..I dont need a processor because the ones im interested in are 50k to 135k. I feel as if I can build this splitter for less then 10k dollars and im okay with that.. Not okay with spending 10k dollars and having a "headache"from it..What do all of you professionals think?


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## triptester (Jan 26, 2011)

Things sound pretty good so far. The part that may be the most difficult will be the wedge design. The blades will have to be narrow and perfectly angled to keep the wood from jamming. The wedge may require only straight grained knot free wood.


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## stihl2009 (Jan 26, 2011)

I was wondering about the wedge myself. Maybe I will go ahead and purchase the wedge that is used on a cord king 60.. I know that is designed for all types of wood. I would then just have to figure out a way to fabricate their wedge to my splitter. Im not going to be selling this,just for personal use...


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## Deereman76 (Jan 26, 2011)

Reservoirs

On Oil resevoir sizing:

This link Says a good Rule of Thumb is 3x Pump Flow/Min. So at 28 GPM, you would need a 84 Gallon Oil Tank. This seems extreme to me, My 16 GPM Splitter holds roughly 8 Gallons of oil, However, My Oil gets a tad hot when working it hard in sub-freezing weather. 

My Gut Says that if you go less than 1X Pump flow, you are going to need to have a big cooling system. More than that, and you might get away with out a cooling system.


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## CountryBoy19 (Jan 26, 2011)

Deereman76 said:


> Regeneration? Problem is, regeneration only works on the extend stroke, not on the retract... I Found this to be a good description of regeneration:
> 
> http://www.hwhcorp.com/ml37939.pdf
> 
> ...


 
The problem with regenerative hydraulics is that your cylinder force is greatly diminished. That's ok where you're just trying to move something very fast with very little force. That's not ok when you're splitting wood.

Your pressure out the end is only going to be equivalent to the area of the rod, not the cap. With a 2 in diameter rod you're looking at 4.5 tons, it doesn't matter how large the cylinder is, if it's a 50 inch diameter cylinder with a 2 inch rod your force at the end is still just 4.5 tons.

The only way to do this IMHO, is if you can find a cylinder that is 7 or 8 inches with a 6 or 7 inch rod. This will increase your extend and retract times drastically (run regenerative hydraulics on the extend, and require very little oil on the retract). However, such a cylinder is going to cost big bucks I think.


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## ray benson (Jan 26, 2011)

Logsplitter tank sizing - about 1 gallon of oil in tank per gpm of the pump. example 16 gpm pump - 16 gal tank.
Frequently Asked Hydraulic Questions, Some common hydraulic questions and their answers


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## stihl2009 (Jan 26, 2011)

Again,Thank you guys so much.. Has anyone built something to this already? If not,why? I looked at the Timberwolf and the Built rites,they just dont have the splitting capabilities that I'm looking for.. I just cant see buying a processor for 80 thousand dollars more then I could build a huge log splitter for. Only reason I could see spending the 80,000 is the fact that there is alot less chainsaw operating time,not that I dont love running the 441.Its just that as we all no the more time you do something the more time there is for something to go wrong. But for 80 thousand dollars. I feel that just being safe and smart and then productive I will be okay..You guys have been awesome and if someone has pictures of their monster splitter they built,id love to see them...


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## triptester (Jan 27, 2011)

I believe the best info you will find is to look at the specs for the proven commercial splitters, Timberwolf, Built-rite, and Split right. When you find a machine with the tonnage and speed you want you will be able to see what has been proven to work.

Regenerative valves have been talked about but I doubt they are cost effective, if they were the manufacturers would be using them.


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## Deereman76 (Jan 27, 2011)

CountryBoy19 said:


> The problem with regenerative hydraulics is that your cylinder force is greatly diminished. That's ok where you're just trying to move something very fast with very little force. That's not ok when you're splitting wood.
> 
> Your pressure out the end is only going to be equivalent to the area of the rod, not the cap. With a 2 in diameter rod you're looking at 4.5 tons, it doesn't matter how large the cylinder is, if it's a 50 inch diameter cylinder with a 2 inch rod your force at the end is still just 4.5 tons.
> 
> ...


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## bejay (Jan 28, 2011)

the cord king 60 is impressive and im sure they cost alot but they didnt skimp on the hydrualics either with a 125 hp engine maybe more depending on options plus multiple pumps rated at 100-130 gpm its easy to see why they are expensive.
while it does more than just split wood.
Ive always wondered why someone hasnt used mechanical leverage along with hydrualic leverage to increase there tonnage wich would in theory let you get by with smaller pump, cylinder, and engine, but seeing how the manufacturers are not using it that I know of it probably has alot of problems to overcome.


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