New to me homebuilt log splitter help

   / New to me homebuilt log splitter help #1  

kilohertz

Member
Joined
Jul 22, 2011
Messages
28
Tractor
John Deere 710
Hi Guys,

I found this site in my search for log splitter ideas as I have many cords of maple and ponderosa pine to split. BIG BIG logs. There are lots of great ideas and splitters posted here. Nice work everyone! Already broke my 8lb maul so it's time for some hydraulics.

I borrowed a friends home made splitter (he didn't build it) to see if I could fix it. It had very little oomph and wouldn't split anything. I took apart the spool valve and cleaned the regulator. I have it splitting some small pieces but it still doesn't seem to be very powerful. It is PTO driven from my tractor, I put an adaptor on the high speed PTO to allow it's use so the pump is spinning at about 1000 RPM. The pump is a dump truck pump by Commercial, 30 GPM at 1200 RPM, factory set at 2000 PSI but who knows if it's been adjusted. The cylinder is 3" X 20". I have also sharpened the blade as it was quite blunt. I am posting some pics to get your opinions on it's profile. Not sure if it's a good design and perhaps, this is why the wood isn't splitting easily. The splitter loads up the 50HP JD 710 tractor so the hydraulics seem to be working. They also get real hot after 15 minutes of trying to split wood. I think I am just dealing with a design issue. My friend doesn't want it and offered to sell it to me for $200 so I think I will go for it and then start rebuilding it.

I am thinking maybe a 4" ram would be better, and change the wedge?? :confused3:

Look forward to your comments.

Update......I just checked the hydraulic fluid and it's quite milky. Yuk!

I also noticed, there is no filter in this splitter so there is the first upgrade to make. Add a filter and change the fluid. That may improve performance.

Update #2

Upon further reading here and investigating the splitter, I found the PRV on the pump, a Commercial C101AR-25, turned it in 2 turns, and put a small washer under the PRV spring in the Gresen control valve spring, as it was turned in as tight as it would go. Now I am getting a little more poop out of this. I was able to split a moderate size piece of pine, but it still won't touch the maple. I put a gauge on this to see what I am getting for pressure and when it trys to split but doesn't, it deadheads at 2000PSI. It loads down the tractor a bit more now when it bottoms out. I think the hydraulics are okay. Probably a bigger cylinder and a new wedge will make this perform better.

Your thoughts?

Cheers

Paul
 

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   / New to me homebuilt log splitter help #2  
The hydraulics should get warm but not hot. Hot means flow trough a restriction. In example if the ram gets hot it leaks around the piston.
Milky fluid is caused by water so it is possible that some parts (such as the ram cylinder) can be corroded. 3" ram should produce about 14000 pounds of force at 2000 psig.
 
   / New to me homebuilt log splitter help #3  
For a point of info... at 2000 psi:
cylinder diameter
3 inch = 14,000 pounds
4 inch = 25,120 pounds
5 inch = 39,250 pounds

I don't like the angle of the wedge. Or anything that might lend a chunk of wood getting airborne. Also, don't weld the rod to the pusher plate. any side load from the wood will bear on the rod seals. Loose is good... :thumbsup:
 
   / New to me homebuilt log splitter help #4  
Change out all the fluid and add a return filter about 10 micron. Sharpen the wedge to a thin angle . Put a pressure gage in the IN port of the valve and monitor the pressure. You can then see what is happening with the hydraulics. Whether it is there, not there, how much , and be able to set the PRV if you know what it should be. If you tighten the PRV all the way, the pressure will build up to the pump pressure, and perhaps blow something up. Could be pump, valve or hoses.
 
   / New to me homebuilt log splitter help #5  
For a point of info... at 2000 psi:
cylinder diameter
3 inch = 14,000 pounds4 inch = 25,120 pounds
5 inch = 39,250 pounds

I don't like the angle of the wedge. Or anything that might lend a chunk of wood getting airborne. Also, don't weld the rod to the pusher plate. any side load from the wood will bear on the rod seals. Loose is good... :thumbsup:

THIS is why you seem to have no power. Thats only 7 tons. Most good units are 20 tons+.

As to the fluid getting hot, if it is indeed a 30GPM pump, those look like some awfully saw lines feeding the cylinder. ESPECIALLY the steel line going to the base of the cylinder.

Is the splitter fast??? Because if you are indeed getting 30GPM efficentally to the cylinder, a 3" x 24" long cylinder only has .73 gallons of fluid on the back side. That would mean it should only take 1.47 seconds to EXTEND fully. I doubt it is actually that fast due to the small lines/restriction and that explains the heat problem.
 
   / New to me homebuilt log splitter help
  • Thread Starter
#6  
Thanks fellows!! I'll answer below, in order of posts.

Redneck - Yes, it gets hot after about 15 minutes of running, and as LD1 pointed out, the tubing is pretty small for this unit.

Hosspuller - The blade is actually 2 pieces of dozer cutting blade welded back to back. Pretty thick and very tall for this machine. As you pointed out, that's what I figured it was putting out as well, about 7 tons. You're right about the sideload...it sometimes gets a bit off centered when the wood is not squarely cut. When I put the new ram in, it will have a floating mount.

J-J - Yup, I have gallons of new fluid for it...going to wait until I change the cylinder though. I also have the filter housing but need to buy the element. I did put a gauge on the input as you suggested, and I get 2000 PSI max when the cylinder bottoms, and as the fluid heats, it drops to about 1500 PSI max. I picked up a new section of dozer blade yesterday, nice and thin (well 1" thick but sharp) and will be installing that after I get the old one cut off. The pump is truely (spec says so anyway) a 30GPM dump truck pump with a max pressure of 2500. I turned in the PRV on the pump 2 turns and that is what gave me the 2000PSI. I could try turning it in some more to see if I can get 2500 PSI out of it. I will also back off the PRV in the control valve, just to be safe.

LD1 - Yes, small lines indeed. The splitter extends fully (24 ") in about 4 seconds, so yes, it is fast. I am running it at about 1000RPM on the fine spline PTO on my JD710. It's 50HP which is overkill for splitting but it's what I currently have to use. I am thinking that a 12 - 15HP gas engine will go on this one day with a new 2 stage pump that I have seen mentioned in numerous places on this site but for now, I only have time for a cylinder change and knife change. I found a nice 4" x 24" cylinder with about a 1.5" rod, at the local heavy equipment wreckers for $75 that should produce about 24,000 lbs. That, combined with a new blade, should get me through this years wood. I still need to build a pole shed and storage for the tractors etc. and am running out of time.

The wood is sitting in my yard and just needs to be processed.

Thank you again all for your ideas. Look forward to seeing further comments.

Cheers

Paul
 
   / New to me homebuilt log splitter help #7  
Do you happen to know if the log splitter valve is designed for 30 GPM's, and if not, therein lies the reason that some of the heat is generated. If the valve is only rated for say 15 GPM's, just run the pump at a speed to produce 15 GPM. A flow meter and gage will help solve all or any problems.

Are your hoses rated for 30 GPM's?

On the pump relief valve, you can probably go about 50 psi below the pump pressure, and also about 50 psi below the valve PRV pressure.

If the cyl is an older used cyl, as the fluid get hot, more fluid will slide by the seals, and also more internal leakage in the pump will reduce the pressure.

Is that a log splitter valve with detent and auto to neutral. ?

The reservoir doesn't look large enough.
 
Last edited:
   / New to me homebuilt log splitter help #8  
If things have computed right, that pump has a 6.9 cu in displacement, pumping 30 GPM, at 2000 psi, and at 1000 rpm.

In order to do that, the HP required would be 41.

In order to get 2500 psi,and 30 GPM's, you will need 51 HP. This would explain why the 50 HP tractor is loading up, maybe stalling.
 
   / New to me homebuilt log splitter help #9  
YOU will want a two stage pump. JJ 's calculations point this out.
 
   / New to me homebuilt log splitter help #10  
A side note here, and that is, have you seen some of the hyd cyl on those waste management trucks. They would need 30 GPM to give them regular speed. I believe your pump is wasted on the current log splitter. Perhaps if you could find a 5 or 6 in bore cyl. Plus those small lines on the 3 in cyl is causing more heat than necessary.

You could run that pump at a lower rpm, and less GPM, and still have the pressure.

15 GPM feeding a 4 or 5 in cyl would work well.

It only takes 21 HP to run that pump at 15 GPM's, and 2000 psi
 

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