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  • shop made hydraulic cylinder question

    Hi,

    Can anyone give me a 101 on making hydraulic cylinders?

    I need to make a few single acting cylinders similar to the ones made by Porto Power or Enerpac. I will be using the cylinders to break beads on industrial loader tires so the pressure will be around 10,000psi.

    I've searched for info on this site and PM, found a few suggestions, suppliers of raw materials etc but still have some questions.

    Thank you,

    Steve

  • #2
    There are likely many here who could answer your questions.

    You just need to ask them.

    Comment


    • #3
      Have fun with holding the tolerances your need for hydraulic cylinders
      Hint: you need something more than a lathe...

      Comment


      • #4
        A peice of dom with an "o" ring grove at the top and plate grooved and welded at the bottom , with a case hardend ground shaft works well as long as you watch the travel.

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        • #5
          Easy, just use hydraulic cylinder tubing and a couple of ends from solid blocks of aluminum fitted with o-rings to seal. Use all-thread grade 8 rod to make it an external tie rod cylinder as that is the easiest way to do it. Buy a cup seal for the piston, about $2 and use a couple of O-rings to guide the rod in the exit end block. Provide a relief vent with a hose barb on the rod exit block so that if any blowby occurs you can save the juice from getting all over everything.

          Keep all fittings that transfer force exactly coaxial with the piston rod.
          Free software for calculating bolt circles and similar: Click Here

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          • #6
            A few observations...

            10,000psi is fairly high pressure. Most industrial systems run at around 3,000psi max.

            Fittings/hose for 10,000psi are relatively expensive.

            I don't know if honed hydraulic tubing for 10,000psi applications is readily available in small quantities.

            I don't recall ever seeing a cylinder with 10,000psi rating with tie rod construction. (I'm not saying they don't exist, I just don't recall seeing any)

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            • #7
              Well, most of the parts are pretty loose tolerance, allowance has to be made for the oil getting hot, there's a bit of give in the various seals etc.
              I prefer welded end cylinders since mounting gets simple. Any distortion of the bore can be designed out with the stroke- a keeper nut on the rod will take up some of the travel.
              Aluminum does make good pistons & guide cap. A well made cylinder will have PTFE ( or an equivalent) wipers plus the o-rings. If you have a small bore UHMW will work in lieu of metal.
              The stationary seal is easily held in with a circlip and absolutely makes maintenance easier, also makes honing the cylinder gravy...don't use threads to hold the stationary end, big PITA.
              If you have side loading in your application think about making the cylinder longer for greatest distance between piston and end cap.
              DOM usually has good I.D. roundness and a ready-to-hone finish though lousy concentricity to O.D. which usually is NBD. The hones with lots of little abrasive blobbies work well. The brand escapes my addled brain presently.
              If you use push stroke only, putting a return to tank isn't a bad idea, keeps the return side lubed and clean. If you have no load to return, you'll have to contend with a spring return.

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              • #8
                I have worked on 10 kpsi systems. I would avoid them for DIY. everything is expensive at that pressure

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                • #9
                  Originally posted by Evan
                  Easy, just use hydraulic cylinder tubing
                  Does hydraulic tubing come pre-honed?
                  "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                  Comment


                  • #10
                    Originally posted by dhammer
                    Hi,

                    Can anyone give me a 101 on making hydraulic cylinders?

                    I need to make a few single acting cylinders similar to the ones made by Porto Power or Enerpac. I will be using the cylinders to break beads on industrial loader tires so the pressure will be around 10,000psi.

                    I've searched for info on this site and PM, found a few suggestions, suppliers of raw materials etc but still have some questions.

                    Thank you,

                    Steve
                    Use aluminum or cast iron for the head, use crome plated 1045 as a shaft. Being its a single acting volume cylender the piston just hold its strait so it can have holes in it or just be a bead of brass braised around the shaft machined with porting to let oil flow to both sides of the piston. the head takes all the pressure. for a volume cylender there is no reason you cant use a 2.875 shaft in a 3" bore

                    For 10,000 psi you best make it real beefy. Iv seen a track hoe with a 10,000 psi system blow a large hose and it made a huge mess. by the time they shut it down it dumped about 40 gallons of oil.

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                    • #11
                      I am betting the OP mean't 10,000 psi force developed rather than that being the working hydraulic pressure.

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                      • #12
                        Ditto Sparky. !0,000 PSI working force

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                        • #13
                          DIY cylinders

                          A buddy made many single acting cylinders using DOM tubing [and sched 40], he turned steel end caps with o-rings for seals, held in by snap rings and suitable diameter ground mild steel shafting. No piston on the end, just the shaft end, although some had a stop bolted on so the unit couldn't overextend. Naturally, this design eliminated the need to hone the tubing. Worked well, never saw one come back. You don't need chromed shafting if you are sure to leave the cylinder in the retracted position when not being used.

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                          • #14
                            Originally posted by dhammer

                            .................................................. ...........

                            I need to make a few single acting cylinders similar to the ones made by Porto Power or Enerpac. I will be using the cylinders to break beads on industrial loader tires so the pressure will be around 10,000psi.

                            .................................................. ..............

                            OP clearly states 10,000psi pressure and similar to Enerpac.

                            Sure sounds like 10,000psi to me...........

                            Comment


                            • #15
                              air/hydraulic pump

                              Thanks, everyone, for the help.

                              The pump I am using is an Esco air/hydraulic pump. Esco catalog says "pump developes 10,000PSI of hydraulic pressure with only 100 PSI of air input"

                              I have a Esco bead pushoff tool that supposedly produces 8,000 psi. I've taken the tool apart to see how it is made. The wall thickeness of the tubing is,..I didn't measure.. but if it is .200 I'd be surprised. I am confused as to the difference between "working force" or "force developed"

                              Just about all hydraulic tools used in mobile tire repair use this Esco pump. I've got two bead breakers, bead pushoff tool, dual tire bead breaker. I need a couple of plain single acting cylinders with strokes appx 2-4" One cylinder oal should be about 4.5" the longer one about 10". To use. one end of the cylinder is placed against the frame of the loader, skidder whatever and the ram is placed either on the wheel ring or close to the tire bead. Apply pressure and things start to move. Commercial cylinders from tire repair suppliers run $300.00 per each .

                              I figure I'd try to make something useful with a shop full of machine tools, learn something new and maybe save a few bucks to boot.

                              Thanks again,

                              Steve

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