log splitter Rota Cyl. hydr. cylinder

   / log splitter Rota Cyl. hydr. cylinder #1  

mgtd

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Joined
Feb 3, 2008
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18
I'm planning to build my own log splitter. Many of the questions have probably been asked and answered in various threads already, but bear with me, I've read this board for hours and appreciate the fact that others may be able to provide concise opinions without re-reading for days.

In salvaging out a trailer mounted solar signboard, for various components to use in current and future projects, I have a cylinder that is labeled "ROTA-CYL Corp. Schwenksville PA. Model Number BJ 11-20-SOLA, spec's are 2" bore, 58 3/16" stroke, serial number S 50324." (YES, nearly 5 foot stroke).

The shaft is 1 3/8" diameter.

This was originally a one way cylinder (raise the sign, with gravity return to down position), however the top of the cylinder housing has a threaded plug and I believe it could be a two way cylinder with additional hose, proper valving et cetera.

Shortening this cylinder to an appropriate length appears as though it would be a relatively easy task, as the cylinder end caps are held in place by 4 threaded rods running the entire length of the cylinder. I would want the stroke to be approx. 32", for firewood for my outdoor furnace.

I also have the 12 volt electric pump and approx. 4-5 gallon reservoir with it's one way valve off of the trailer. I'll probably utilize the reservoir.

Rota Cyl has a website, but doesn't offer any product descriptions/spec's and if they did, this was probably a specific use, non catalog item anyway.

My questions are:
1) Can I assume the "20" in the model number may indicate a 20 ton cylinder? And might the 11 indicate 11 gpm--or reverse?

2)What gpm pump would be best for moderately rapid actuation?

3)What size gas engine would be appropriate for properly sized pump.

Here are some pi's for clarification.

Thanks for any help.
 

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   / log splitter Rota Cyl. hydr. cylinder #2  
Couple of comments
An 11gpm double stage pump wants 5hp min gas engine or 2hp elecetric motor, which is how I run mine with a 4" cylinder. Pretty standard for small splitters.

I don't think a 2" bore cyl is going to do it.

With a 2" cylinder the pump will be in low speed high pressure most of the time. High pressure is what the the relief valve is set at ,usually 2250 psi .
The 2 inch will run faster but the available force is 25% of the 4".
It's a balancing act between pressure and speed. I have never seen a spitter with a 2" cylinder. I suspect you would need 10,000 psi at the relief valve,
 
   / log splitter Rota Cyl. hydr. cylinder #3  
Just my opinion, but I feel that a 2" cylinder is too small for a log splitter. I know you would like to use the one you have but I don't think that you will ever be happy with it. Look for a 4" cylinder minimum. I think that will work out much better for you.
Ken
 
   / log splitter Rota Cyl. hydr. cylinder #4  
mgtd,

I don't believe it is worth the effort to use what you have. A 2 in bore with 1 and 3/8 shaft at 2500 psi will only push 7,864 lbs, and at 3000 psi, it will push 9,425 lbs.

You would be better off using something like this, min of 2 in shaft. You could go with a shorter cylinder if you want shorter firewood.

Burden Sales Surplus Center Item Detail
 
   / log splitter Rota Cyl. hydr. cylinder #5  
I agree with the other posters a 2" shaft would be minimum for a splitter, especially of this length. My father and I are building a 4' log splitter. We have a 5" cylinder with a 2" shaft. It is mounted on a large I-beam with a shorter cross I-beam at one end. This unit is welded to the top of an axle from a log truck. This winter we area going to put the hydraulic parts on it. It would be nice to put it to use next summer. I have an outdoor furnace which will handle 60" wood. I think 48"' wood is more comfortable. We also have to design a log lifter for the unit. We are using a PTO pump and a reservoir which holds about 25-30 gallons.

Good Luck,

Mike
 
   / log splitter Rota Cyl. hydr. cylinder #6  
4inch minimum. with 12v electric it won't be fast and you will need a few batteries charging while you are using one to split. With the time and effort to build one, you just as well make one that will do the job. You will be happy you did.

If interested, the one I made is on youtube. woodsplitters, plumbstriaight. Watch the spelling as I messed up putting it in. I did a note a while back on it, but might give you some ideas.
 
   / log splitter Rota Cyl. hydr. cylinder #7  
I agree the cyl. you have is way to small and to light. I think you would bend the rod on the first log.
 
   / log splitter Rota Cyl. hydr. cylinder #8  
While I believe the rod size is fine for the power you will have, the 2" piston will only give you @ 4 tons of splitting force. Depending on you wood that may leave you a number or knarly blocks you can't split.

On the other hand I have a 4" piston, 1.5" rod on my splitter cylinder and find The pressure rarely gets to 1000 psi b4 the block splits and I can shear a 6" cross grain at @ 1500 psi. It's way over powered, which just results in slower cycle times. Either a 3" or a 3.5" would work faster for me with enough power.

4" cylinder pistons do seem to be the most common, mainly because most splitter manufactures don't want you back grumbling that its short on power.
You may find 2" works for you if your wood splits easy. If you do use it I would design so a larger cylinder could be added if needed though.

If you had a buddy with a splitter I'd buy him some beer and a pressure guage to install in his splitter and then take a few tough looking block of yours over there to see how many tons you really need to get the job done by obseving the max pressure it takes to split the wood. Then you can design your splitter to your needs
Ken
 
   / log splitter Rota Cyl. hydr. cylinder #9  
Use that cylinder for another project. Get a 24" stroke 4" dia cylinder.

Chris
 

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