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  1. #16
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    Nov 2007
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    melbourne australia
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    I had a look at the splitter today. The thread is very badly damaged and bent. It's definitely not repairable.
    The "grub screw" is a bolt with a lock nut. It hasn't moved, so I don't believe the ram had unscrewed itself from the clevis. I reckon the threaded part has been bending for some time and the cast iron clevis eventually cracked from the stress.

    I think I'm going to have to fabricate a different type of clevis. I don't think the threaded design is robust enough. One idea is to cut off the damaged end of the ram and make a hefty MS or 4140 sleeve that slips over the ram. I would probably weld two 16mm thick tabs to the sleeve to form a new clevis. I'm open to suggestions as to how to secure the new clevis to the end of the ram.
    Attached Images Attached Images
    Chris

  2. #17
    Join Date
    Apr 2012
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    Healesville
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    G/day jack, you could cut the damaged end off and bore and thread the rod and make a stud to screw into it.
    Or.....it looks as though you have enough meat there to turn another thread on the rod, then you would have to
    make up the missing length on the new nut for the chopper bit.
    Personally l think l'd go with the 1st suggestion and make a stud out of 4140
    shed

  3. #18
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    Nov 2007
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    melbourne australia
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    Thanks Shed. A stud would be a good solution, but I was hoping to avoid disassembling the hydraulic ram. I have no experience with hydraulics and my lathe spindle is too small to take the ram anyway.
    Chris

  4. #19
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    Aug 2011
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    Melbourne
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    Hi Jack,

    Sorry to hear that. Whatever you do, you need to make sure that the piston and rod is still long enough so that when it retracts, the piston still sits hard up inside the cylinder end. An hydraulic cylinder's stroke finishes when the piston hits the end of the bore internally. If you shorten the rod by cutting and re-threading and it is shortened then the stroke will be limited when the rod or clevis hits the end of the ram which is not good design. If you need to shorten the stroke in order to re-thread the rod then you can add a stroke limiting disc inside the cylinder. That way the stroke still finishes when the piston hits up against the wall or a spacer that sits against the wall.

    Anyway, the above may be completely off track so just ignore if that's the case. Another option, which may seem a little harsh is to cut the threaeded part of the rod off, fabricate a new clevis than then just weld in onto the end of the rod. If you have some length spare you could bore the clevis so that it still slides over the rod and then run a weld over the join. Or, of course cut a new thread 0n the rod and fabricated clevis and rejoin, which is what I did.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  5. #20
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    Nov 2007
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    melbourne australia
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    Thanks Simon. If you look at the first photo in the post above you can see the red paint on the end of the ram. That is where the ram stops when it's fully retracted. I'd guess there's around 70mm of ram plus the threaded bit to work with.
    Chris

  6. #21
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    Apr 2012
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    Healesville
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    If you feel like a drive to my shed we could sort it out, I have 58mm bore on my lathe, i think I should
    have some 4140, what dia is the thread, 7/8"?
    I probably have o rings to suit that cyl also, if they are needed that is.

  7. #22
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    Nov 2007
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    Thanks for the offer Shed. I may have to take you up on that. The thread is 32x2mm. Much bigger than I estimated.
    Chris

  8. #23
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    Apr 2012
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    no worries I think that I have some 50mm 4140, think about when you want come over and p/m me and we will work it out.

  9. #24
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    Aug 2008
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    near Rockhampton
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    Not enough photo's for me to determine the cause, but given only minimal pull back force is required, you could just hold a new end on with a cross pin.

    I am wondering if it is a chinese made hydraulic ram. I would have expected the rod to snap before it bent like that. Have seen them bend in the middle, but the ends snap off.
    Gold, the colour of choice for the discerning person.

  10. #25
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    Nov 2007
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    Quote Originally Posted by .RC. View Post
    Not enough photo's for me to determine the cause, but given only minimal pull back force is required, you could just hold a new end on with a cross pin.
    That was my original thought. If I made a cross-drilling guide I might be able to drill the hole for the pin with a hand drill. How hard are these rams typically?

    Quote Originally Posted by .RC. View Post
    I am wondering if it is a chinese made hydraulic ram. I would have expected the rod to snap before it bent like that. Have seen them bend in the middle, but the ends snap off.
    I strongly suspect it is Chinese RC. At least the steel might be easy to work!
    Chris

  11. #26
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    Apr 2012
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    Quote Originally Posted by jack620 View Post
    That was my original thought. If I made a cross-drilling guide I might be able to drill the hole for the pin with a hand drill. How hard are these rams typically?
    You will be able to drill through the threaded/machined part, but if you are thinking about drilling through the chrome, umm good luck with that

  12. #27
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    May 2011
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    Murray Bridge S Aust.
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    If the ram is Chinese, the thread may not be a true 32 X 2, either in the clevis or the ram. Causing movement, which eventually caused it to let go.
    Kryn
    To grow old is mandatory, growing up is optional.

  13. #28
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    I thought that I would have a look before I opened my yap too wide, I have this cylinder that I repaired maybe 2 or 3 years ago. I don't remember what it needed doing to it, probably a loose piston nut as that was fairly common on these cylinders. When they leak at the rod seal this is usually the problem.
    The biggest problem with them is that the bore is not always coaxial to the outside of the cylinder and then they cut they the lead in chamfer, maybe coaxial and then it is uneven to the bore, when the end cap is pushed on the uneven chamfer it cuts the o ring and they leak.
    When you pull the cyl off make sure to keep all of the mounting alignment shims together and labeled as to what stud they came off, I have a feeling that misalignment of the rod to your chopper may be your problem here, when you refit the cyl you need to extend the rod out and make sure that the clevis hole lines up with the chop chop hole, if it doesn't then you need to move those shims around until it does, it is a pain as you might have to do this half a dozen times before you get it right.
    Anyway, this cylinder is 125mm OD, the rod dia is 44.88mm, studs 17.9, bolt Patten is 106mm, end cap to end cap is 695mm, if it is the same as yours l will swap it as this is just a cyl that l have for an unknown future project.
    Or if you want we can repair your gnarly rod, I had a look and I have seals and o rings for these cylinders.

    cheers, shed
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  14. #29
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    Thanks again Shed. That's a very generous offer. Your cylinder appears to be identical to the one on my machine. I'll have to pop over to my mate's house and measure mine to confirm. Thanks for the advice on the shims too. It makes sense that misalignment would place a lot of stress on the ram/clevis joint, particularly when the ram is retracted and the ram can't flex.
    Chris

  15. #30
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    Aug 2011
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    It seems that bore misalignment with the external dimensions is not uncommon. My splitter uses an Eaton/Vickers cylinder and when I was modifying it to suite my purposes I noticed that the bore was not in close alignment to the external dimensions. When I shortened the barrel I made sure the bore was aligned and not the external before facing to final dimension. I was then that it became obvious that there was considerable runout on the OD even when the ID was true. I nearly fell into the trap of assuming they were aligned, using the DI on the OD when facing.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

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