Homebuilt Splitter - Seems Slow...

[Millman]

Return is slow

Hi Guys, I have a similar problem. My return is slower that the extend stroke on my splitter. I talked to a number of hydraulic people here at work and their reasoning is there is less surface area for the oil to push against on the return stroke. I am using a massive dump truck cylinder with very little room between the cylinder walls and the shaft. I bought it used and it also looks like the return port was added later which makes sense why it would go slow. I think it was only meant to be a single action cylinder. Any thoughts? Also pressure on the return stroke is about 650 PSI and on the extend below 200.

~Millman

 

[CylinderService]

Slow logsplitter

Stew,
You've made a nice splitter. The valve is almost certainly the part that's slowing it down. It's rated at 16-20 GPM but that doesn't say how much pressure it takes to drive that much oil through it. Changing to a Prince logsplitter valve will probably help a lot. We sell a lot of them (at the lowest price I've seen around) and everyone seems happy with them. I agree w/ Casey, changing fittings & lines might help some, but not nearly as much as the valve.
Using a lighter oil is OK until it warms up, and in very cold weather. When it's not so cold, the oil may lose some of its lubricating properties (film strength) and make your pump wear out prematurely.
By the way, your method of calculating cylinder speed is right on, if a little unconventional. For the record, Pi r squared x length gives cylinder volume in cubic inches, there are 231 cubic inches per gallon; dividing cylinder volume by pump output yields fraction of a minute for cylinder stroke (out).
See CylinderServices.net for these valves and all the Prince hydraulics.
Good luck with it!

Don the hydraulics guy

 

[CylinderService]

Millman's slow return...

If your return takes 650 PSI, that's a lot. Either there's a lot of mechanical friction, or too much hydraulic restriction. You may be shifting a two stage pump into the high pressure stage, which is only about 25% as fast as the low pressure stage.
If there's no unusual mechanical restriction, use hoses & fittings big enough for the flow your producing, and get your return pressure down to a lower level. 3/4" is the size most normal size splitters use for the return line, and 1/2" to & from the cylinder. Dump truck cylinders aren't usually practical for logsplitters. It might require a very large line from the base of the cylinder all the way back to the tank.
Single acting cylinders are not usually made strong enough for retraction pressure. They usually leak a lot, and sometimes it will break the gland out. Just wear your safety glasses while you're using it, which is a good idea anyway.

Don the hydraulics guy

 

[MS-310]

So what is a good way to make a fast splitter????? I want an fast splitter just cuz I do it by hand now and its fast but not always the best way.

 

[rb_in_va]

Stew,
Your splitter looks very nice. One question I have is why did you built it to force the block into the maul, instead of the other way around? Admittedly I am not a splitter guru, but it seems to me that it would be more efficient to force the maul into the block.

 

[tawilson]

I like it set up that way so I can use a 4-way wedge, and to so it pushes the split wood off the end of the splitter into a pile. I've never used one the other way, but wouldn't you have to handle the split wood again as it splits to get it out of your way?
Oh, by the way, welcome aboard Don, I've recommended your services here a few times after I ordered the autocycle valve from you a couple of years ago.

 

[Stew182]

Thanks for the feedback guys.

Using a lighter grade oil was mentioned. I am using H32 Hydraulic oil (got it for free, so that's what I used). Is the oil I am using the right kind, or is it possibly too thick and slowing the flow down? I dunno...

What grade of hydraulic oil is recommended for most systems?

Another question I have is, should I remove my gauge from the extension fitting on my cylinder, and put in-line between the pump and valve??
Would there be any PSI reading at all (with no load) on my 0-5000 PSI gauge if my valve is restrictive?

rb_in_va,
I have my wedge stationary because the majority of my wood is about 6"-12" round, so most of it only has to be split once. The ram shoves all the split wood into a pile off the wedge end.


I will probably have to wait until spring to get a new Prince valve, and possibly a 3/4" pump to valve hose.

Thanks guys,
Allan.

 

[CylinderService]

Stew’s splitter

Notes on all this stuff:

I usually recommend attaching the ram to the flat pusher, and fixing the wedge to the beam, like Stew made his. Wedges attached to rams may pull the rod off center - not good for the cylinder, sometimes even bends the rod. Stew’s reason makes a lot of sense too.

Tom Wilson, thanks for the referrals! Nice to hear from you in a little different forum.

Stew,
H32 is a good weight oil, probably the lightest you should use.
Putting the gauge in front of the valve (inlet side) will tell you how much pressure it takes to drive the oil thru it (sometimes called “pressure drop”), when the valve is in neutral. This is the standard location for a gauge - it tells the total load on the pump. Normally a pump might lose 5 - 10% of its flow going thru a too-small valve, but with a 2 stage pump 650 PSI may be enough to cause the large stage to drop out, reducing the flow by about 75%.
You may be doing this already, but most people remove the gauge when they’re through checking & adjusting things, and install a pipe plug while they’re just splitting wood. Not that we don’t like selling gauges

Fast Splitters: Ram speed is a product of pump flow (GPM) and cylinder size (volume). With pumps, more GPM = more speed (pressure - PSI - affects ram force, but NOT speed.) However, the power (Hp) required to drive the pump is determined by the product of pressure AND flow. More speed or more force requires more Hp.
With cylinders, the less oil it takes to fill it, the faster it will go. So smaller bore cylinders are faster. But of course, smaller cylinders also put out less force at a given PSI. My personal opinion is that many home builders of logsplitters go overboard when selecting their cylinders (too big), and then pay for it by having to live with a slow cycle time. 4" bore is enough, unless you're using a multiblade wedge. Not that we don't like selling big cylinders

Don

 

[rb_in_va]

I usually recommend attaching the ram to the flat pusher, and fixing the wedge to the beam, like Stew made his. Wedges attached to rams may pull the rod off center - not good for the cylinder, sometimes even bends the rod. Stew’s reason makes a lot of sense too.

Thanks for the info! I asked because most commercial models that I have seen have the wedge attached to the ram.

 

[Booshcat]

Most of the commercially available splitters will operate in a horizontal AND vertical position. I like to use mine vertically when splitting big rounds as I can spin the log onto the bottom plate instead of lifting it up onto the beam.
I don't see how you could run them this way with the wedge at the base as you would have to balance the log while waitng for the flat ram.

 

[Stew182]

Don,
When I get the time to put my gauge in the inlet side of my valve, what PSI range should I be looking for when extending the cylinder, with no load, at full throttle ?

The way I have my gauge now, in the extension port of the cylinder, there is 0-PSI gauge reading on cylinder extension with no load.

I am just trying to determine if my valve is too restrictive, or if my pump is faulty, or if something else is wrong. I wish I had a flowmeter.

On the Haldex 2-stage pumps, are there any adjustments that can be made other than the unloader valve ( to increase pressure, or flow) ??

Also, does anyone know if there is a user manual online somewhere for these pumps?? I cant seem to find one.

Thanks again,
Allan

 

[Firewoodster]

Post a Splitter Pic

Thanks to the help of Don the Hydralic MAN I'm going to post a pic of my Splitter very soon............It "will" rock your socks.

down for now, but comin' up !!!!!!!!!!

Two HUSKY 36's and hopefully a 262XP delivered tomorrow.........!!!!!!!!!!!!!

 

[CylinderService]

Allan,
With your gauge in front of the valve, I'd expect 100-200 PSI, although a lot less would be nice. PSI x GPM divided by 1714 = Hp in a hydraulic system, so at 200 PSI you would be using about 1.9 Hp just to push 16 GPM through the lines.
Haldex 2-stage pumps: I think the only adjustment is the unloader pressure, and I don't recommend adjusting that. If it's set too high you risk putting too much torque on that little shaft. And Haldex certainly doesn't encourage repairing them. Years ago when I dealt with them, we tried to get some seals and it took about 6 months of constant badgering to get them. I think they use thin cellophane gaskets between sections too, which are usually ruined when the pumps are taken apart.
On the other hand, if they're set up well, with a good shaft coupling, lined up carefully, plenty of oil always available to the inlet, and system relief set to a reasonable level (2500 PSI), they last a long time.

Don