Re-doing log splitter build

[nathan125]

Mt father in law in engineering the splitter. He has a 5" cylinder with a 2" ram, believe 24" stroke. The pump is 11gpm and with a 5 horse Subaru engine.
I realize it's not going to win any races but I wonder how slow it will be.

I bought a 8hp Honda engine and a 13gpm pump but he doesn't think it will work and expressed it would be very time consuming to re-do the pump and engine.

I feel it would be better with the set up I suggested but I lack much in way of skills and I know he wants to get this splitter done with and finish it.

My question is how much better is the set up I suggested and how will the performance be with the splitter he is building?

 

[jetsam]

By way of reference... The DHT 30 ton has a 4.75" cylinder (faster), a 15 GPM pump (much faster), and a 6.5hp engine. It is rated at about 15 seconds for a 24" cycle. All other things (fittings, lines, valve flow rate) being equal, I would guesstimate that he's looking at a 20-25 second 24" cycle.

5hp is probably enough for an 11 gpm pump, but an 11 gpm pump is not enough to move a 5" x 24" cylinder very fast.

I'd be interested to hear what he actually gets!

 

[triptester]

Here is a link to calculators. These calculations are for max rated rpms, lower rpms will reduce output proportionally.
.(broken link removed to http://www.baumhydraulics.com/pages.php?pageid=4)

 

[jetsam]

The cylinder speed calc says that in a perfect world (no bottleneck at hoses, valves, fittings, engine) that cylinder will cycle in 20.1 seconds- so my guesstimate was probably a little optimistic, especially once you put that 5hp engine under some splitting load.

 

[VirginiaIron]

Just the 5" cyl alone is going to increase your tonnage if it is larger than the original and this would be the easiest route, imho, but it will slow down the travel. I do not think the 2 gpm increase is going to be worth the effort and would opt for a 5" bore with a 3 or 4" rod. If you get a larger rod, your return speed will increase- this is helpful since you really do not need any tonnage to retract or dislodge your wedge, if applicable.
Here is a force calculator to determine force for the increase/decrease on bore/rod diameter tonnage push and pull per psi fluid/not gpm.
http://www.calculatoredge.com/mech/pushpull hydraulic cylinder.htm

 

[VirginiaIron]

I need to r&r my leaky valve and for curiosity I am going to look to see if my pump has an internal restrictor threaded inside the pump outlet body when I remove the hose. I am thinking by removing this, if present, my gpms will increase.

Something similar to these that can be simply unscrewed.
(broken link removed to http://starperf.com/images/custom/REN/42000.jpg)

(broken link removed)

 

[VirginiaIron]

Paging Jags...
Paging Ashful...

 

[jetsam]

Honestly, it might not matter much. Maybe he plans to use the splitter for the really tough stuff and split most of his wood with a maul. Or maybe he is retired and doesn't care if it has a 60 second cycle time.

 

[VirginiaIron]

Honestly, it might not matter much. Maybe he plans to use the splitter for the really tough stuff and split most of his wood with a maul. Or maybe he is retired and doesn't care if it has a 60 second cycle time.

Yeah, time wasn't a consideration for me until I started reading this forum. I've seen faster splitters before but I really didn't care about the subject that much.

 

[jetsam]

I didn't care either until I started using hydraulic splitters. When you have a big gnarly piece of elm, 60 seconds is a big improvement over sledge'n'wedge.

 

[VirginiaIron]

In the past when I had some medical issues, moving and splitting the small/med & larger sized logs was difficult. When I got the splitter all I had to worry about was the logistics of moving from point "A" to point "B"- placed on the beam, so the cycle time was icing on the cake no matter how long it took. With those health problems well past me I am mindful still of the hazards. Selfishly, I think it would be nice to finish in half the time, or just sip tea and whatch someone else split the wood- thank you YouTube and Vimeo.

 

[Jags]

I run a 5" cylinder with a 16GPM pump. I wouldn't want it any slower. When working rounds that require several splits, I find myself waiting for the return stroke to open up. If something ever happens to this engine/pump combo in the future - this thing will be getting a 28 GPM pump with a 14+hp power plant.