Hydrualic cylinder question

[wrench191]

I bought a large hydrualic cylinder to use for a log splitter I plan to make. I think it came off of a crane. The case is 36 inches long but it has just 25 inches of travel.There is
about 12 inches of ram sticking out when retracted.My question is do they ever put a spacer in to limit the travel? If they did, is this something I could remove?

 

[mga]

if they did, i can't see why you couldn't.

 

[m37]

Yes some times they do put spacers in hyd rams. if you can open the cyl then you can remove the spacer. What dia is the ram?

 

[wrench191]

8 inch its a monster. I would like to have at leat 30 inches of travel.The ram is at leat 3inch. It will be slow but powerful.I thought I would make it 4way or 6way split to make up for the long cycle time.I have not made one before but I am doing a lot of reading on here.

 

[Kevin in Ohio]

A 6 inch cylinder with a 28 gpm 2 stage pump has about a 30 second cycle time so yes, you are looking at a VERY slow cycle time. You'll probably be able to stack the wood and walk back by the time it cycles. The problem lies with the valves and gpm. I'm building mine at the moment and had my heart set on a 6 inch but reverted back to a 5 when I started talking to someone who has built them for years. Honestly. 6 inch is overkill. You get into a danger zone in my opinion going that big. You can break some serious steel with that much force. Bolts can be missles.

The wood splitter type valve for high gpm pumps are pretty few. I know of one but it costs about $1500.00. More gpm means huge lines(over 1 inch) and if you don't you're just choking it it down and you will have heat problems.

What gpm pump are you thinking of running? Probably someone on here can figure the cycle time for you but I bet you will be shocked. I'm guessing close to a 2 minute cycle time with a 28 gpm pump. Just trying to give you a heads up on what you're in for before starting the build.

 

[wrench191]

AS I said I have been doing some reading.A 16gpm pump,8inch cylinder,3inch ram,25inch travel. Extend Time= 20.8 sec. Retract Time= 17.9 sec. Cycle Time= 39 sec.

Not nearly as slow as you thought.

 

[wrench191]

A 28gpm pump,8inch cylinder,3inch ram,25inch travel.
Extend Time= 11.9 sec. Retract Time= 10 sec. Cycle Time= 22 sec.

Log Splitter Speed Calculator by International Hydraulics

 

[timbrjackrussel]

AS I said I have been doing some reading.A 16gpm pump,8inch cylinder,3inch ram,25inch travel. Extend Time= 20.8 sec. Retract Time= 17.9 sec. Cycle Time= 39 sec.

Not nearly as slow as you thought.

That is at 16GPM.
A 16 GPM 2 stage pump would drop to 4GPM (8horse power) at higher pressure. A 16 GPM single stage pump would need 16 HP @1500PSI, and 32HP @3000PSI.
It would take a strong frame to hold it, but what a splitter!!

 

[Steve NW WI]

That is at 16GPM.
A 16 GPM 2 stage pump would drop to 4GPM (8horse power) at higher pressure. A 16 GPM single stage pump would need 16 HP @1500PSI, and 32HP @3000PSI.
It would take a strong frame to hold it, but what a splitter!!

True, but:

A 2 stage pump only slows down when pressure rises above the set point (not sure excactly, but if we use 500PSI, an 8" will develop 12 tons of pressure before it even kicks down to the low/speed high pressure side.) My guess is most of his splits will never make it shift down.

I'm just guessing here, but I think your stroke is probably only what you have, maybe a couple inches more are possible, but in a cylinder that size, there's a pretty substantial piston on the end of the rod. The extra length on the rod is likely just to get the needed length for it's original application.

BTW, I run a 7" x 28" cylinder on mine with a big single stage pump run off a tractor PTO. It ain't fast, but it doesn't stop either. My cycle time is close to 20 seconds full extend and retract, probably average 12-15 while splitting (not running full length).

As Kevin mentioned, it needs big valves and hoses (read $$$) to move this kind of oil. Mine are 1" on the pressure side, with a 1.75" return line.

 

[RVALUE]

I believe the "3 inch ram" is unnecessary information.

 

[wrench191]

I know I am just a beginer but I think the size of the ram affects the return speed.Also most pumps say a 16gpm pump need a 8horse motor.A 28 gpm needs a 16hp motor.

 

[Kevin in Ohio]

AS I said I have been doing some reading.A 16gpm pump,8inch cylinder,3inch ram,25inch travel. Extend Time= 20.8 sec. Retract Time= 17.9 sec. Cycle Time= 39 sec.

Not nearly as slow as you thought.

Sounds like you have it down. That 8HP motor with 16gpm pump will do great on fuel too. Keep us updated with pics of your progress and outcome.

 

[bayard]

39 sec

39 sec is very slow,it will drive you nuts.the one i built is 9 sec at full rpm.at 3/4 rpm is 13 sec full cycle. a 11hp honda and a 21 gal pump.the piston dia. is 4 inch. and a 24 inch travel.k

 

[wrench191]

I am considering a 28gpm pump. I have a couple of 18hp engines.
cycle time Extend Time= 11.9 sec. Retract Time= 10 sec. Cycle Time= 22 sec.
If I use a log lift and split 4 ways.But what I really want to know is. Is it likely that this
cylinder has a removable spacer in it.

 

[RVALUE]

I am considering a 28gpm pump. I have a couple of 18hp engines.
cycle time Extend Time= 11.9 sec. Retract Time= 10 sec. Cycle Time= 22 sec.
If I use a log lift and split 4 ways.But what I really want to know is. Is it likely that this
cylinder has a removable spacer in it.

My guess is no.

You can improvise the short stroke with a block of wood to help split the FEW that don't cooperate. It is pretty fast, especially if you can stop the strokes without going full cycle.

I would also imagine your cycle time to be longer than the math dictates. Those darn variables like friction etc.

 

[wrench191]

This is what m37 said. Yes some times they do put spacers in hyd rams. if you can open the cyl then you can remove the spacer.
I am not dissbelieving him. But before I take it apart I would like more people to agree with him.

 

[Richard Dupp]

The 3" ram you speak of, is that a 3" rod? If so that will speed up the return stroke some. Anyhoo, with an 8" cylinder and 2000 psi, you will have 50 tons of force. What are you planning to split? It may be a little overkill. The pump will likely only kick down on some pretty tough stuff, and your cycle times may be a little slow. All in all, I would be more concerned about heat buildup more than anything. You will be pushing a lot of fluid through those hoses and some form of cooling might be worth considering.

 

[CJ1]

I bought a large hydrualic cylinder to use for a log splitter I plan to make. I think it came off of a crane. The case is 36 inches long but it has just 25 inches of travel.There is
about 12 inches of ram sticking out when retracted.My question is do they ever put a spacer in to limit the travel? If they did, is this something I could remove?

Yes it is common for cylinders in equipment to have what is called a stop tube or stroke limiter in them, most of them are a collar or sleeve that goes over the piston rod if it is the front of the piston. So you have to take the cyl apart and pull the piston off and slide the stop tube off. I have only had 1 cyl in 15 years that has had a stop in the bottom of the barrel and that was a home made one. CJ

 

[Fifelaker]

This is what m37 said. Yes some times they do put spacers in hyd rams. if you can open the cyl then you can remove the spacer.
I am not dissbelieving him. But before I take it apart I would like more people to agree with him.

They are not that hard to take apart. so add me to the agree list unless there is no spacer :hmm3grin2orange:

 

[Kevin in Ohio]

I am considering a 28gpm pump. I have a couple of 18hp engines.
cycle time Extend Time= 11.9 sec. Retract Time= 10 sec. Cycle Time= 22 sec.
If I use a log lift and split 4 ways.But what I really want to know is. Is it likely that this
cylinder has a removable spacer in it.

I'm assuming you have no idea what it came off of? If you did know that you could look for a parts blow up from manufacturer. Just a thought. Like others said, it is common but to find out shouldn't take very long to do when you take it apart.

With a 28 gpm pump plan on 3/4" hoses on main ram/pump and a 30 gallon holding tank(minimum). Make sure to have a diffuser on return in the tank and a baffle will help too. Avoid 90 degree fittings and get a filter that is designed for that much flow. You'll blow a standard one on the return.

Just curious, what to the books say is the proper beam size to use with 8 inch? Lots of force there.