Log Splitter Question(s)...Two Stage Pump and Situation Specific Questions

[6sunset6]

Thinking a little more about your valve selection. I think the two valve block is fine, except that you might want a detent pressure release on the retract motion. This allows hand on the valve holding for extend or split and then pushing or pulling the handle for retract and letting go. Retract will stop by itself when it hits the end of the stroke. IF you are doing logs shorter than the cylinder stroke you can clamp a sled stop on the beam and the retract will stop there. I went with the full auto valve and it is not worth it. Half the time it does not go into auto retract so I have to hold my hand on the valve anyway. If the machine runs fast enough you cannot move away anyway.
You might want to consider a third spool if you ever want to add a wedge lifter.
With respect to speed control use 1/4 hoses for the lifter. With a 22gpm pump you might have to restrict further, Even with 16gpm I feather the valve quite a bit. Restrictor fittings are available . They have a very small hole in them. Or a needle valve in one of the lines. get one with out a check , then it works in both directions.
You should look for a cylinder with the largest diameter rod available. Mine is a 4.5" diameter with a 2.5" diameter rod. Not so much for the retract speed ,although that is a factor, but for the bending load on the ram. A 5" cylinder with a 40" stroke will more than likely flex the beam, try to lift the sled, and generally stress the whole system. Mine does that occasionally and I am learning how to avoid it. Mostly watch the knots.

 

[LD1]

Our splitter is a 27T tsc huskee. Uses the 4.5" cylinder. I think it is a 2" rod, but could be 2.5???

We have never had any issues with the rod whatsoever. But regardless wether you choose a bigger rod for strength or for speed, it is a good Idea to get the biggest you can.

 

[Scooby074]

If your running a 22gpm 2 stage, you need more than 11 hp. 14 minimum if you want to keep it at ~2000PSI, 16 or 18 if you want to go higher in pressure. Anything much above 2200 psi with that 22gpm pump will stall the engine.

-Dont care what the "figures" say, in practice more HP (within reason) is better.

 

[MGH PA]

I am thinking for the tank, it should be about 1.5 times the GPM of the pump. However a lot of commercial log splitter use smaller tanks .

It seems that modern day hydraulics for mobile hyd is going to smaller tanks and perhaps adding a radiator and fan to help cool the fluid if needed.

If you are wanting to build a beast, then go for the 5 or 6 in cyl, but I doubt you will ever use the potential that the large cyl will provide.

If you look at the size cyl that most log splitter have, it is the 4 in cyl.

At 3000 psi, a 2 in bore cyl 1 in rod, will develop about 8 ton.

-----------------3 in-----------1.5----------------------------10 ton

-----------------4 in-----------2.0----------------------------18 ton

-----------------5 in-----------2.5----------------------------29 ton

There is a lot of over kill with large cyl, as most splitting is done using the 4 in cyl.

If you put a hyd gage in the system, you will see the pressure that is developed at each moment. It is usually high pressure briefly, then the pressure falls off as the log is split.


Larger cyl cost more.

Speed is mostly determine by the GPM of the pump.

If you want to get fancy, there is the log splitter auto valve where you set both levers, and the log is split and the rod returns automatically, then the log lift, and the hyd wedge cyl for up/dn.

Fancy wedges that can split 4 ,6, 8 pieces at one push.

http://www.tractorbynet.com/forums/power-trac/183187-log-splitter-3.html

Go to post #26 and you will see a nice configured log splitter.

The splitter wedge is stationary, and the wings move .

Big homemade log splitter - YouTube

Dad's Wood Splitter - YouTube

Yep, I saw those links earlier on here when I was researching. Awesome splitter. I don't know if I need a hydraulic wedge as it does add to the complexity, and most of our splits aren't extraordinarily large diameter (hence the lack of need for a box or 8 way wedge...a four way might be nice however).

So a 4" would be sufficient for my needs?

As a side note, I have a sheet that has most of the major hydraulic formulas on them, and what order you should go in to arrive at the different specs for a log splitter, but it starts out by figuring GPM through a predetermined retract/detract speed. I'm not AS concerned with that, so is there a formula I'm overlooking that can arrive at GPM requirements in a more simple fashion? I'm a little leary now hearing from Scooby that 14HP would me the bare min if operating at 2000psi, since that engine was the max size I had planned on going with, and I'm assuming a dropping down in pump size may not generation the force needed on the longer logs we need to split.

Thinking a little more about your valve selection. I think the two valve block is fine, except that you might want a detent pressure release on the retract motion. This allows hand on the valve holding for extend or split and then pushing or pulling the handle for retract and letting go. Retract will stop by itself when it hits the end of the stroke. IF you are doing logs shorter than the cylinder stroke you can clamp a sled stop on the beam and the retract will stop there. I went with the full auto valve and it is not worth it. Half the time it does not go into auto retract so I have to hold my hand on the valve anyway. If the machine runs fast enough you cannot move away anyway.
You might want to consider a third spool if you ever want to add a wedge lifter.

Thanks, didn't think about the detent pressure release. That may be a good thing to have so we can work the splits up while it's retracting (either pull them off the catch grate, or flip them for a second split).

What is the main advantage of a hydraulic wedge?

 

[J_J]

If your running a 22gpm 2 stage, you need more than 11 hp. 14 minimum if you want to keep it at ~2000PSI, 16 or 18 if you want to go higher in pressure. Anything much above 2200 psi with that 22gpm pump will stall the engine.

-Dont care what the "figures" say, in practice more HP (within reason) is better.

This pump is rated for 3000 psi and requires about 12 HP.

Surplus Center - 22 GPM 2 STAGE HYD PUMP S31004-5278

Sure one could use more HP, but the relief is going to go off at the relief pressure at about 100 psi below the pump max pressure.

 

[LD1]

The numbers dont lie. (PSI x GPM)/(1714 x eff) is the industry standard.

A 85% efficient 22gpm 2-stage calls for 13.3HP. If 14hp wont run it, someones numbers are wrong. Either the motor is overrated, or the pump efficiency is off, or it is trying to make more PSI or GPM than claimed.

 

[Scooby074]

The numbers dont lie. (PSI x GPM)/(1714 x eff) is the industry standard.

A 85% efficient 22gpm 2-stage calls for 13.3HP. If 14hp wont run it, someones numbers are wrong. Either the motor is overrated, or the pump efficiency is off, or it is trying to make more PSI or GPM than claimed.

Yep. Know the calculation. Been tested on it matter of fact Efficiency percentage must be way off on these.

As I said, rather than run it right to the margin, real world says more hp is needed. I posted the Barns 22gpm 2 stage chart on the other thread. @22gpm, 750 PSI, it requires over 15hp. This is pretty much what ive seen in person.

If I start increasing max press, ill end up using all my available hp (assuming again that the engine produces what its rated at) at over 2600. Again, what Ive seen in practice.

If you want to get a Barnes up to max press of 3000, its going to take well over 12 hp mentioned above, probably closer to 18. Im not saying surplus center (and hp calculations) are wrong.. but they are "wrong".

 

[LD1]

Im not saying surplus center (and hp calculations) are wrong.. but they are "wrong".

:confused2::laughing:

Maybe its just YOUR set-up of motor.

I tell you what is even more confusing....

I was trying to look up some factory 22gpm splitters and see what they use...

The timberwolf TW-5 uses a 337cc honda gx340 motor. According to hondas website it is 10.7hp (BUT they actually list it as a 389cc):confused2:

And their TW-6 uses a 688cc motor for the SAME pump????

Iron and Oak does indeed use a 11HP motor with their 22gpm as well.

And when you think about it, the 22gpm pumps are exactally double the 11gmp pumps. And most of them only run 6 or 6.5 hp motors.

I hear what you are saying though. Obviously your 14 HP motor wont run the pump past 2200psi. BUT, like I said, it must just be your motor or something. Cause Timberwolf and I&O certainly wouldnt sell a splitter that would stall in nasty stuff.

 

[J_J]

Prince uses about 2750 psi relief pressure on some of their log splitter valves, an based on those settings, the pump will never develop max pressure, and less HP is required. If you tweak the log splitter valve some, you might use all the available HP, and you would know this as the engine would start to stall.

A lot of the manufacturing company's over state their numbers on their products.

7 GPM at 2750 psi = 13 HP

If your 14 HP motor is stalling at 2200 psi, something is not right.

 

[Scooby074]

LD, I dont know how IO and TW are doing it.

My motor is brand new, out of the box. Rated at 14Hp, but who knows what it is in reality. Remember that class action suit a few years back.

As I said in the other thread, Looking at the curve for the Barnes 22 gpm, 11 hp can do 22gpm, but at only 2000 psi. 14Hp should theoretically be able to give a little over 2500 maybe 2600(?), but I couldnt get mine to be reliable at those pressures. As I clarified in the other thread, I ended up at 2200PSI mostly because it was a reliable pressure. I might have been able to squeeze a bit more out of it, but was having other issues with the splitter too.

Maybe IO and TW only set theirs up at 2000 sys press? If so 11hp should run it.

Im guessing the reason they run the bigger motor on the TW6 is so they can run higher pressure on the LP side and HP side. The TW6 is 2 tons more than the tw5 with the same cyl so sys press must be higher. If you have the lp shift point set at 750psi and max press at 3000 your going to need all of 15 and likely 16 hp. The TW6 is 2 seconds faster on the cycle time than the TW5. The 688cc Honda is about 20Hp peak. The way I figure it, ignoring the calculations, that's about what you need if your going to max out the pump on LP and HP and have a bit of fudge factor built in.