Question about hydraulic pressure for splitter

[jkbemdavis]

Hi.. I have posted previously about plans to build a splitter and am a regular lurker on this forum, but needed to post this question. My buddy and I are building the splitter... it is almost finished and pics will be posted when it is. One piece of heavy duty hydraulic lines that we bought was just a tad too short. Rather than going out tobuy new hose, we have hooked up a piece of regular black metal pipe as an extension. My question is, to your knowledge will that pipe be durable/strong enough to handle the hydraulic pressure that builds up or will it be a safety issue?
Thanks,
John

 

['bert]

Yes to both. It will most likely hold the pressure, but it is a safety issue. The black pipe works but does not have required PSI rating for hydro. Just remember if it fails that hydro oil that will blast you is gonna hurt.

 

[JeffRey30747]

What section of the hydraulic circuit will the pipe fitting be a part of (pressure, return or suction)?

 

[Gooserider]

I forget the exact number, and it depends on the pipe size a bit, but black iron is rated for around 2-300PSI maximum safe pressure... This is plenty for the suction or return lines, but it is NOT a safe bet for the pressure side which normally can reach 3,000PSI before the popoff opens - or better than TEN TIMES the rated pressure... You might get away with it - my friend's 20 ton has a black iron elbow on the pressure side, which I don't particularly like, but it hasn't blown yet. OTOH, I can tell you that hot hydraulic showers are NOT fun...

(On my splitter, when I needed extra length, I ended up getting a bunch of HIGH PRESSURE fittings...)

Gooserider

 

[jkbemdavis]

Thanks for the replies... but crap! Well, I'd rather get things done right than possibly end up hurt. The pipe is 3/4" and it is on the pressure side of things. I'll just have to go out and get another proper length of hydraulic hose. Thanks again for the thoughts, and I'll post pics once it is done.
John

 

[Gary_602z]

How short is it? Maybe you can take it up with a couple extra hydraulic fittings or just have a short extension hose made up at TSC or a tractor dealership.

Gary

 

[jkbemdavis]

We're only talking about a 7 or 8 inch pipe. I'll check into that.

 

[k3c4forlife]

Hydraulics aren't something to mess with. They are one of the most dangerous parts on a home made splitter... Personally I would try to figure out if you could move the pressure side closer together before going out to buy a new hose. Maybe you can remount the cylinder further back to make up the difference?

 

[Gooserider]

Hydraulic hoses aren't all that terribly expensive... I know my local hydraulic shop will custom make whatever I need for around $50 or so, or you can go online to a place like Burden's Surplus Sales and get a pre-made hose for about half that if they have what you need... (Depends on the fittings) From the purist standpoint, you are a little better off with a single hose, no adapters or splices, as those add restriction to the fluid flow, which will make your unit run hotter. I think you'd also find the difference in cost between making / purchasing a splice hose vs. a single hose the length you need would be pretty small... Most of the cost in a hydraulic hose is the ends and the assembly labor, the actual hose itself is fairly cheap, on the order of $3-5 / foot...

Gooserider

 

[WES999]

FYI McMaster Carr http://www.mcmaster.com
Has thick and extra thick black iron pipe rated for 3K and 6K psi. Plenty for a splitter application.

 

[jkbemdavis]

FWIW,
I decided to post a quick pic of the work in progress. Obviously not finished yet. The Hydraulic cylinder needes to be mounted, and the splitting ram placed back under the guides. The black pipe can be seen pressure side between valve and cylinder, as well as a couple of elbows. We will likely make changes based on the recommendations here. Once everything is done, I'll wire brush the beam, then paint her up nice, and should be good to go. I'll post pics again when done.
John

 

[Gooserider]

I see a few potential issues; some may be real, some might just be due to only having the one picture that might not show everything, so take it for what it's worth...

1. The suction line - it may be the photos, but it looks awfully small bore. Plus that clear braided line tends to be good on resisting pressure, but will still collapse easily under suction.... The suction line, and it's fittings should be at least one size larger than the pressure line, and should be made from a wire reinforced hose, or have a coil spring inside it so that it can't collapse...

2. I don't see any filtration - you should have a hefty filter in the return line to the tank (and nowhere else - especially not anything on the suction line...) It should be easy enough to do that, as it looks like you have several sections of pipe in the return line that could be replaced w/ shorter nipples and a filter...

3. While theory says you should never put Sched 40 black iron pipe anywhere on the pressure side, it is relatively less likely to be a problem on the cylinder return circuit, as that side should never actually see more than a few hundred pounds of pressure, as it never gets any real load when retracting the piston... On my splitter I see around 200psi on the gage when it is returning hot, 300 cold... I still wouldn't recommend the black iron on the pressure side, but in that location you can probably get away with it... (OTOH, the pump-valve and extend side lines DO see full system pressure, which is more of a problem)

4. I hope the cylinder mounting block is WELDED (substantially) to the beam, not just held on by the bolts I see in the picture - I suspect that if it's just bolted you will learn the hard way about the shear strength limits of bolts...

Otherwise, it looks like you are doing a good job, plenty stout and all that...

Gooserider

 

[jkbemdavis]

Gooserider,
You are absolutely correct about the filter being needed. That is one of the pieces we are still working on. The stock that the cylinder will be mounted to is welded very stoutly. It was not so initally, and there was an issue on a test run, so the system was revamped with a nice weld and reinforcements put in place also. I'll get back to you on the supply line information.
Thanks again,
John

 

[Gooserider]

Gooserider,
You are absolutely correct about the filter being needed. That is one of the pieces we are still working on. The stock that the cylinder will be mounted to is welded very stoutly. It was not so initally, and there was an issue on a test run, so the system was revamped with a nice weld and reinforcements put in place also. I'll get back to you on the supply line information.
Thanks again,
John

As I said, there were some things that just don't show in the photos - I looked at that stock, and I could see the bolt head, but not the weld, so I thought I should mention it... You should have no trouble getting a filter housing and filter, its a standard item at any hydraulic shop, or the Surplus Sales place I linked to earlier has them, your local NAPA probably has them as well or can get one... (and black pipe is no problem at all on the return side...)

Gooserider

 

['bert]

I am guessing this is a horizontal only splitter (maybe there is a pivot under the axle that I can't see). If so, from the pic it seems to be a bit low to the ground, just a thought, I built mine so that I do not have to hunch over while using it. Your back will thank you in the years to come. Here is a picture of my homebuilt contraption.

 

[Gary_602z]

Here is mine ready for action!