New and yup, ANOTHER log splitter project

[Wineslob]

Hi all. I "stumbled" across these forums while searching for "how to build a log splitter"
I've been a maintenance man/plant engineer/stupidvisor in a coating manufacturing plant for over 20 years. I do everything from, fix tha chit to design and build what we cant find, don't have, ect. So I can weld, machine, and figure out how to make it work.

On to the log splitter. I've trolled here for roughly 2 weeks getting as much info as possible. I've got all the parts to start construction of this project.

1. I'm on a very restricted budget.

2. WAF of monies spent on this is very low, see #1

3. I went with the 18" "log splitter" cylinder from here: https://www.surpluscenter.com/item.asp?UID=2009083113122534&item=9-7178&catname=hydraulic, 11gpm 2500 psi 2 stage pump, and the "log splitter" control valve.
4. My wood burning stove is designed for 16" firewood (max, trust me), so I'll never be splitting anything longer. Most rounds I get are 18" and smaller in dia. Thats why the 18" cyl, plus at $40 it works with #1 & 2. I've got it at the house and the quality is pretty darn good for the money. So no worries about it being crap.
5. Most of the wood around here is pine, walnut (orchards), oak, or almond (orchards again). Nothing really 'hairy" to try and split.

Now I've got a "bug" up my butt. I'm just throwing this out there. Could I run 2 of these cyl in tandem? Say, one one top of the other? Would this double the tonnage? (my best guess would be 16 T)
At a cost of 40 bucks for one more cyl, it's doable (see #1 & 2) and I like to think up stuff like this .

Thoughts?

 

[J_J]

Sure could, splitting will be slower with two cylinders. The 11 GPM will be divided equally between the two cyl. Pressure will be 650 psi in the fast made, and 2500 psi in the slow/power mode. Join the two ports, with a tee fitting, one hose from the valve to the tee for each end. You did not say anything about a log splitting valve.

Two cylinders would act like a 6 in cyl with a 3 in rod. force would be 70,686 lbs, or 36.8 ton using 2500 psi in the slow mode . 12 sec extend, 9 sec to retract, with the toughest wood, a shorter time with pine.


ERROR, ERROR, DARN IT.

 

[Wineslob]

JJ thanks. Wow the tonnage is crazy. Much more than I thought it would be.
The valve is this one: https://www.surpluscenter.com/item.asp?UID=2009083114041629&item=9-7724&catname=hydraulic if thats what you are asking?

I may have to re-think the double cyl, I only have access to 6" I beam, I don't think it could take the stress.

 

[J_J]

At 2500 psi

3 in cyl---------8.8 ton
4 in cyl---------15.7 ton
5 in cyl---------24 ton
6 in cyl---------35 ton

 

[rus_geek]

Sorry to correct you JJ, but two three inch cylinders don't make a six inch

Area of a six inch cylinder would be about 28 square inches, where two three inch cylinders would only have about 14. You'd need *four* three inch cylinders to get that tonnage.

-rus-

 

[Grand_Pooba]

Sure could, splitting will be slower with two cylinders. The 11 GPM will be divided equally between the two cyl. Pressure will be 650 psi in the fast made, and 2500 psi in the slow/power mode. Join the two ports, with a tee fitting, one hose from the valve to the tee for each end. You did not say anything about a log splitting valve.

Two cylinders would act like a 6 in cyl with a 3 in rod. force would be 70,686 lbs, or 36.8 ton using 2500 psi in the slow mode . 12 sec extend, 9 sec to retract, with the toughest wood, a shorter time with pine.

JJ I learn something interesting every time I read one of your Hydraulic posts....but I've jump in on your calcs. (2) 3" bore cylinders would give you an piston area of 14.14 sq in. A 6" cylinder would be 28.27 sq in.
Force for (2) 3" cylindeers at 2500 psi would be 35,350 lbs.
Doubling the dia. increases the area by a factor of about 4.

Thanks
Steve

 

[Grand_Pooba]

Sorry JJ not ganging up here. Rus and I must have been typing at the same time.

 

[J_J]

Sorry JJ not ganging up here. Rus and I must have been typing at the same time.

That's Ok, I am old and tired, and I am looking at a lot of numbers on my scratch pad. Two 3 in cylinders would equal a little more tonnage than a 4 in cyl.

I put the correct numbers up above.

 

[Wineslob]

Thanks for the corrections guys. Looks like I just might give it a try.

 

[bassgrinder]

The way you would calculate how much force you would get with multiple cylinders is to multiply the force each cylinder has times the # cylinders However you also have to consider that when you mount them if they cock the slide and make it bind you will lose some or all of that. I have seen one built with 2 cylinders side by side and it would sometimes bind so bad it would stop itself halfway with no block. From what you describe the wood you will mostly split, you may get by with one cylinder for about 12 tons, if you put the wedge on the ram then you can have the ram retract power get any block that gets stuck on the wedge back off, which is by far the worse case scenario when you are under powered.
Going by your first post your best bet may be to use the one cylinder, make it as cheap as possible and be happy with whatever it will do with 12 tons. Just go into it understanding that you are building a 12 ton splitter, with splitters the tonnage is a general yard stick, the higher the tonnage the more it is going to cost to buy or build, period. The only way to cheat that is to find high tonnage parts for sale at a low tonnage price.
I have seen 12 ton units do a nice job on wood like you have described, the problem would come if you tried to compare your unit with a 35 ton unit. Point is, if your gonna need a 35 ton unit, then wait until you can find a 4” cylinder and such that you can afford (Ebay, Craig’s list, local auctions etc). But if you can truly make do with, and want a 12 tonner then go with what you have and build it simple, and fast.