Splitter Hydraulic Question Revisited

[oldnslo]

If piston is fully separated from the rod, the rod will come out at full extention....and so would a lot of oil...

Not on a log splitter where both ends are rigidly attached unless they left enough free play between the wedge and pusher.

 

[AKKAMAAN]

Not on a log splitter where both ends are rigidly attached unless they left enough free play between the wedge and pusher.

****...I hate when my fingers are typing faster than my brain thinks.....


Do your pusher hit the wedge at fully extended???

If not at least that will happen when rod comes of the piston.....

 

[J_J]

This is an EXTREMELY DANGEROUS ADVICE!!!!
Note that there is NOTHING that protects for over pressure.......This is like using an old Webster flow meter, with out the safety soft brass washer that cracks at over pressure......I have cracked one saftey washer on a Webster.....and it was not fun at all........


What people do not realize, is that a needle valve get very progressive the more closed it gets....while wide open you might have to turn it 1 full round, for a 200psi increase of pressure....but at 2500psi, less than 1/4 turn can pop the pressure to 5000psi or more....it all depends on needle valve characteristics and pump flow....

IF something goes wrong turning that needle valve....you might have 4000-8000 psi at a burst and could get killed or severly damaged from oil injection, and "grenade" splits.....

If you want to do this test, you must put an inline Relief valve between the pump and the needle valve.

Safety first, but,

Did I not say, do not to close off the needle valve all the way. Some of those needle valves have about 5 to 10 turns, so I think that some pressure would be indicated on the gage way before you closed it down all the way. We are talking about backyard mechanics here, not a full blown test bench. The relief valve is a good thing, and letting someone else check it out on a test bench would be even better. Just using the log splitter is a risk in it self.

I am glad you brought that out though. Just what was I thinking.

 

[AKKAMAAN]

Safety first, but,

Did I not say, do not to close off the needle valve all the way. Some of those needle valves have about 5 to 10 turns, so I think that some pressure would be indicated on the gage way before you closed it down all the way. We are talking about backyard mechanics here, not a full blown test bench. The relief valve is a good thing, and letting someone else check it out on a test bench would be even better. Just using the log splitter is a risk in it self.

I am glad you brought that out though. Just what was I thinking.

I blow a safety washer on a turbine flow meter once....oil (16gpm) sprayed 150ft from a 1/4" hole......lucky no one was in line near by....so I know what it takes to make a little mistake on the needle valve.....NOTHING....

I think it was a 420bar/6000psi safety washer....

 

[J_J]

Just a reminder what hyd fluid can do. He almost lost his arm. They finally got all the fluid out, but had to take out some flesh also.

 

[woodsroad]

Not on a log splitter where both ends are rigidly attached unless they left enough free play between the wedge and pusher.

Yes, but that ram will move a good bit faster without the piston attached, and you will not be expecting it to happen in the retracting stroke! There was a recall last year on several brands of splitters, where the retaining nut came off. One poor soul lost a hand when the wedge came shooting out in the return stroke. I had the same thing occur on a Harbor Freight log splitter, but I caught it before the nut came off all the way. Saved by a half of a thread!

The HF splitters, btw, have a lot of sideways play between the cylinder and wedge, so you at least get a warning when fluid gushes out past the front seal....

 

[NCMau]

Thanks everybody for the technical advices and the invaluable safety tips as well. I am just about convinced the cylinder had it and I should receive a new one shortly.