# Hydraulic Pump and Ram sizing



## NPKenny (Oct 19, 2011)

I am beginning a splitter build after a bit of research on tonnage, psi, etc.. I have decided to build to meet a few design criteria that I want that don't exist in the lower cost splitters. I am sure it will be a wash in cost, but I will have the splitter configuration I want and the satisfaction of building it.

I am starting with an 11 HP horizontal Briggs and Stratton Industrial motor that is in excellent shape.

I need a bit of help in deciding between a 16 GPM or 22 GPM two stage pump. I know that my engine is just on the edge of being too small for the 22 GPM pump (recommended 12hp) and that in actual operation it will not usually run at peak HP, but don't have the operating time with either to know if the 16 GPM pum is going to perform better.

I am leaning towards as a 5"x24" ram. With a two stage pump, I would think this ram should be plenty fast at either 16 or 22 GPM. However, should I be looking at 4" rams as well? I haven't identified which ram manufacturer I will go with and I have a ton of access to ag. equipment.

I know all of these pieces work together to perform optimally. There are a few trade-offs that I don't have the experience to answer which way I want to lean with these.

Thanks.


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## jags (Oct 19, 2011)

Hmmm...depends. What do you normally split. Ugly old elm or straight grained stuff. Large rounds or average rounds??

A 4" with the 16gpm pump would make a nice, fast splitter with power to do 98% of most peoples firewood. I run a 5" diameter cylinder with a 16 GPM pump. I could use a little more speed, and if I ever have a need to replace the pump, I will go with the 22 or 28 GPM version.

Your 11HP should actually pull the 22 GPM pump unless you crank the relief valves up to the 3000 PSI range. Keep it at 2500 PSI - and it should do well.

My suggestion is:
4" ram = 16 gpm pump
5" ram = 22 pump (you don't have enough engine to pull a 28 GPM)

If your really looking for action - use a 22 GPM pump on a 4" ram. WHOO HOOOuttahere2:


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## NPKenny (Oct 19, 2011)

jags said:


> Hmmm...depends. What do you normally split. Ugly old elm or straight grained stuff. Large rounds or average rounds???
> 
> ...
> 
> ...


 

Usually all elm, Osage orange, mesquite, and mulberry. Maybe up to 30" rounds.


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## rancher2 (Oct 19, 2011)

NPKenny said:


> Usually all elm, Osage orange, mesquite, and mulberry. Maybe up to 30" rounds.


 I split a lot of the same wood you do and I run a 28GPM pump on a 6inch cylinder on one splitter and a 28GPM pump on a 4inch cylinder on my other splitter and I use the one with the 4 inch cylinder the most. Go with a 22 GPM pump and a 4inch welded cylinder with a 2 inch shaft. YOU will love the extra speed that pump and cylinder will give you. Make sure you build a sharp wedge with a good set of wings on it.


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## leon (Oct 19, 2011)

*Wood splitter UGH!!!*



NPKenny said:


> I am beginning a splitter build after a bit of research on tonnage, psi, etc.. I have decided to build to meet a few design criteria that I want that don't exist in the lower cost splitters. I am sure it will be a wash in cost, but I will have the splitter configuration I want and the satisfaction of building it.
> 
> I am starting with an 11 HP horizontal Briggs and Stratton Industrial motor that is in excellent shape.
> 
> ...







About your splitter building adventure and your intent 
on beating your self up with the the (*&^* thing.

I want to save you headaches SO;

A. you need only a small volume 12 gallon per minute "normal" 
gear or vane pump for your task.

B. if you purchase a double acting telescoping cylinder to do the 
work you will have more power to split wood with than you will 
know what to do with.

c. the telescoping cylinder has more piston area than a double acting 
cylinder does and it will be faster as the rod sections have less square 
area to allow faster oil flow.


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## Iron man (Oct 19, 2011)

I'm not liking the telescoping cylinder idea.The first stage of the cylinder would have the most power and be slow.The second stage would get faster but have less power.Works fine on a transmission jack but don't see an application for it splitting wood.

A 5in with a 16gpm is fine.Its what I have and get the job done.If my pump ever takes a dump Ill look into a 22gpm as a replacement.I had a 4in with the 16gpm and its faster for sure and didn't seem to have any problems splitting anything.


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## leon (Oct 20, 2011)

*log splitter*

The telescoping cylinder offers the user 
more pressure per square inch to use 
at all times.

If you look a pressure rating chart for 
telescoping cylinder you will see that.


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## ccarpen4753 (Oct 20, 2011)

I am curious to see a telescoping cylinder splitter setup. Been cruising this site for awhile and havent heard this suggestion come up.


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## Steve NW WI (Oct 20, 2011)

leon said:


> The telescoping cylinder offers the user
> more pressure per square inch to use
> at all times.
> 
> ...


 
Bullhockey Leon. As you reach max extension of each stage, the fluid acts on the end of the next stage, effectively a smaller bore cylinder.

Here's a chart from customhoists.com, check it out here: Double Acting Telescopic Cylinder Product Information, Hydraulic Cylinders: Custom Hoists, Inc., Ohio

Telescopic cylinders are also prohibitively expensive.


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## jags (Oct 20, 2011)

leon said:


> The telescoping cylinder offers the user
> more pressure per square inch to use
> at all times.


 
This is physically impossible. It goes against every rule of fluid dynamics. Just say'in.


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## ponyexpress976 (Oct 20, 2011)

4" with a 22gpm...that's gonna be fast! keep an eye on your fingers with that combo!


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## leon (Oct 20, 2011)

*hydraulic cylinders*

About cylinders;


Commercial Intertecs telescoping cylinders are 
capable of moving up to 153,000 pounds of weight
when in use, when you take that into consideration 
for a log splitter look at the thrust it can create to 
split a block using the the stroke and the pressure 
of the wood blocks resistance.

If you mounted a telscoping cylinder barrel end first 
on a pusher plate you would have zero issues with 
stubborn wood blocks.

The 5 and one half inch cylinder in your example is 
capable of lifting 47,500 pounds of dead weight 
which is what will translate into much larger force to 
shear firewood at lower fluid flow volumes especially 
if the cylinder barrel is mounted facing forward and 
attached to the pusher plate.

A double acting cylinder with a 5 inch piston in push
mode only creates 39,270 pounds of force at 2,000 P.S,I.
I hope this illustrates what I am trying to explain to you.

I would think the additional 8 plus tons of pressure would
be worth the effort.

You can find this information at www.engineeringtoolbox.com


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## jags (Oct 20, 2011)

leon said:


> About cylinders;
> 
> 
> Commercial Intertecs telescoping cylinders are
> ...


 
I am not arguing the capabilities of the cylinders. It all comes down to surface area and pressure. The math does the rest. A 6" diameter telescoping cylinder will not produce MORE pressure than a standard 6" cylinder if the cross sectional surface area and pressure are the same. It really is just math.


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## Steve NW WI (Oct 20, 2011)

Leon,you want 47500 out of a std cylinder, get a 5.5 bore cylinder. Compare apples to apples.

All the tele cylinder does is add cost and complexity over a standard SAME BORE SIZE cylinder. It AIN'T gonna be faster. You need the same volume of oil to move either.

Got stubborn wood? Get a 7" cylinder at a Cat salvage yard. Works for me.


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## CJ1 (Oct 24, 2011)

leon said:


> About your splitter building adventure and your intent
> on beating your self up with the the (*&^* thing.
> 
> I want to save you headaches SO;
> ...


 
I don't know if this is a true or false post but I will answer false to all of the above.
A. You would need 20+ E/B horsepower to use a 12GPM single stage pump at 2500PSI.
B. piston area is the same on out stroke so same force.
C. ???? Faster oil flow???? It could be faster on the return stroke because of more rod Dia. But wayyy more expensive.


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## bayard (Oct 24, 2011)

*22gal- pump*

i have 22 gal pump with a 11 hp honda.4 inch dia. cyl, very fast with most wood .1/2 to 3/4 rpm is all you will need..k


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## kevin j (Oct 26, 2011)

telescopic cylinders have the most area and most force at beginning of stroke, for hard to start loads like dump trucks. but the area drops off as the sections reach extension, thus more speed and less force. 

Double acting telescopics will be at least 10x the cost of a simiilar surplus center standard cylinder. Single acting cylinders with gravity return, like said dump truck, are much cheaper, but still much more than a standard cylinder. The reason for use on dump trucks is simply the space for packaging the cylinder inside the frame. If a long cylinder could stick out the bottom, that is what they would use for reasons of cost, reliability, etc. AgressiveHydraulics does most of our cylinders and they have some cool, but expensive and complicated, telescopic designs.

Pressure is a result of LOAD, not pump. Pump and relief valve only limit the maximum pressure the system can develope to protect it from overload. 
If you had a pressure gauge on a 5 inch cylinder with a 100 gpm pump or a 100 hp engine, no matter. Splitting pine the pressure will be very low. splitting elm, the pressure will be high. Until the pump reaches unloading pressure, or goes across relief, the speed will be constant based on the fixed volume pump flow. Only the pressure and thus load on the engine to turn the pump, changes.


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## Axlerod74 (Oct 26, 2011)

Any of you guys ever used a PTO driven pump off a bucker/augger truck? I am in the process of building a splitter and I have acces to a junked truck with 6" leg jacks or 4" boom jack. I have no idea what the GPM would be of such a pump or what HP requirements it would have. Any thoughts would be helpful. Is the PTO driven pump even feasable in a wood splitter?


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## Frank Boyer (Oct 26, 2011)

Go with a 5" cylinder. Speeco's 35T has a 5" and it does very well. Smaller cylinders cycle fast without a load, but really slow down when trying to split tough stuff. Your beam needs to be much stronger/heavier with a 5" bore than a 4" bore. Look at the difference in numbers on the chart.


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## DIESELBOB (Oct 27, 2011)

*ram*

When I made my splitter I used a 24x 41/2 cylinder. Works great.


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## WidowMaker (Oct 27, 2011)

This site has your answers...
Baum Hydraulics Corp :: Spec Calculator


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## Oliver1655 (Oct 31, 2011)

In reply to the original poster, I split the same types of wood you are & have a 16 gpm 2 stage pump with a 4" tie rod (2,500 psi) cylinder & initially had an occasional piece of elm that I had trouble splitting. My wedge at that time did not have a sharpened edge & the basic "V" of the wedge was at 30 degrees about 8" long then I had another wedge inserted behind that which had a 90 degree angle to "pop" the wood. After looking at lots of log splitter pictures & reading as many threads, I cut off the "Pop" wedge & sharpened the 30 degree wedge. Since then I have not had any problem with it not spitting anything. (I have a log lift & have split up to 42" rounds.) I am happy with the cycle time. Would I go up to a 22 gpm 2 stage pump if I have to replace the 16 gpm? It would be tempting if I found one for less than $250.

Another poster asked about using a pump & reservoir from a dump truck. Yes it would work, however remember, the pump is only a single stage pump & the cycle time will be *A LOT slower.* If it is in your budget, stick to a 2 stage pump & you will be much happier.

Keep researching & Happy Building!


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## tnttreeman (Nov 3, 2011)

I currently have one of the Huskee 35 ton splitters and it has a 5 inch cylinder and a 12.5 hp Briggs engine with a 16 gpm pump. Anyone have any idea how much change there would be to the cycle time if changing to a 22 gpm pump? According to the TSC website, the machine has a 15 second cycle time, but I don't think it's actually that slow. More in the 12 second time, but not nearly fast enough.


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## WidowMaker (Nov 4, 2011)

Did you check the link in my above post, there are "plug in the numbers" calulators on that site that will answer all those kind of questions...


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## tnttreeman (Nov 4, 2011)

I didn't see that, but I will check it out. Thanks.


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