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  • Need info on Christensen hydraulic press

    This weekend's latest tool score was a 40-ton Christensen hydraulic press:



    Price was a reasonable $150, but as is the case for most of my purchases, it needs work. The seller said there's something wrong with the pump, possibly even parts missing. I haven't opened it to look. It's a side-mounted reservoir with two handles- apparently one is high-volume to move the ram quickly, the other is low volume for power.



    Any chance someone has a diagram or manual for this pump? Possible source of parts? Exploded view?

    Doc.
    Doc's Machine. (Probably not what you expect.)

  • #2
    Take it back,the pump is missing the dipstick

    Oh Ya,you suck too
    $150,you powerful suck

    Now that we have that out of the way,those pumps are dirt simple,should have just check balls and some o-rings inside,McMaster should have all the rubber you'll need.
    I just need one more tool,just one!

    Comment


    • #3
      Originally posted by wierdscience
      Take it back,the pump is missing the dipstick
      -That tube on the near corner in the photo isn't for a dipstick, it's for an unpressurized return line from the ram. (Probably just a drip tube for seal weepage.)

      And yeah, this was kind of a stealth tool-gloat post. Nyah!

      Currently trying to dismantle the pump. Not having much luck- I think an O-ring is jammed in a snap-ring groove...

      Doc.
      Doc's Machine. (Probably not what you expect.)

      Comment


      • #4
        Okay, I finally have most of the pump module disassembled. An interesting unit, made largely of fabricated pieces welded together, and then enclosed in a thick steel tank.

        The seller, as I noted above, seemed to think there were actually parts missing from the pump. That's probably true, since the high-volume pump cylinder only contained these parts:

        The ram and it's threaded cap...


        ... a check ball...


        ... and this ring/spacer with a crosspin.


        I suspect the check ball was supposed to go under the spacer, and seat on the opening at the bottom of the pump's tube.

        But there's no seal or wiper or O-ring on the ram, and no packing or seal of any kind- nor a groove or step to accept one- in the threaded cap. As I was dismantling it (still with oil in the reservoir) it'd leak oil profusely as the ram was raised.

        I'm assuming there's some sort of seal I'm missing, and possibly some part (a cup?) on the ram, but I have no idea what they are or what they look like. Anyone have any suggestions or sources?

        Doc.
        Doc's Machine. (Probably not what you expect.)

        Comment


        • #5
          Ya.looks like the piston is missing,easy enough,just machine one up from Aluminum and machine a groove for one of these "O-ring loaded lip seals"-

          http://www.mcmaster.com/#mechanical-seals/=ccd5c3

          If the threaded collar has no seals,which it wouldn't need anyway,I would cut a groove for and install a wiper seal like the "shaft wipers" just to keep dirt out.

          A new ball bearing for the checks,I usually get two,one of which I weld to the end of a 1/4" rod and use for a lapping tool to polish the rust off the seat.

          Oh,and there should be two checks on the HV cylinder,one inlet ball and one spring loaded outlet check.
          Last edited by wierdscience; 05-17-2011, 09:59 AM.
          I just need one more tool,just one!

          Comment


          • #6
            Wow, what a score! Looks like the stiffeners are 1/2" plate -- don't make them like that anymore!

            You've assembled quite the professional machine shop Doc -- it's come a lone way since your 9x20
            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

            Comment


            • #7
              I love how you guys buy things take them apart and make a real repair, or work out what's wrong. I find this stuff really interesting keep up the good work and great press wish |I had room for one although I would probably never use it in reality.Alistair
              Please excuse my typing as I have a form of parkinsons disease

              Comment


              • #8
                Originally posted by wierdscience
                Ya.looks like the piston is missing,easy enough,just machine one up from Aluminum and machine a groove for one of these "O-ring loaded lip seals"[.]
                -I'm assuming the piston would go above the existing steel disc? And that it'll tighten against the taper to seal the inner bore of the piston?

                If the threaded collar has no seals,which it wouldn't need anyway,I would cut a groove for and install a wiper seal like the "shaft wipers" just to keep dirt out.
                -So there shouldn't be any oil above the piston?

                Oh,and there should be two checks on the HV cylinder,one inlet ball and one spring loaded outlet check.
                -There's check balls everywhere. I got at least five out of this thing. There's two checks between the handles, one below the handwheel, and one at the bottom of each pump. I was planning on replacing all of them, as several have rust, but that's a good idea on the lapping of the seats.

                Doc.
                Doc's Machine. (Probably not what you expect.)

                Comment


                • #9
                  Originally posted by lazlo
                  Wow, what a score! Looks like the stiffeners are 1/2" plate -- don't make them like that anymore!
                  -Actually, they're closer to 5/8", and the uprights are 3/4".

                  And they must not make 'em like this anymore- I can find exactly one small photo online of another Christensen, a 25T on a machine sales site. No info on the company, no info on the presses, no one else seems to have mentioned their press in passing on a board somewhere...

                  The date on this thing is something like 9-68, and was sold by Star Machinery Company out of Seattle/Spokane. But apart from knowing that, it appears to be an old orphan brand now...

                  Doc.
                  Doc's Machine. (Probably not what you expect.)

                  Comment


                  • #10
                    Or you can do what I did, replace the hand pump with a port-a-power pump. Electric, that is.

                    Comment


                    • #11
                      The seller said that what he'd intended to do, but before he could, he got a good deal on a 50-ton Dake.

                      It's always possible, of course, but I'd prefer the manual pump for the time being. (That and I'd rather not blow $300+ on an electric power pack at the moment. )

                      Doc.
                      Doc's Machine. (Probably not what you expect.)

                      Comment


                      • #12
                        Originally posted by Doc Nickel
                        -I'm assuming the piston would go above the existing steel disc? And that it'll tighten against the taper to seal the inner bore of the piston?
                        Yes,that's what I am seeing.

                        Originally posted by Doc Nickel
                        --So there shouldn't be any oil above the piston?
                        If there isn't a seal in that cap,then there couldn't be,it would leak every stroke.


                        Originally posted by Doc Nickel
                        --There's check balls everywhere. I got at least five out of this thing. There's two checks between the handles, one below the handwheel, and one at the bottom of each pump. I was planning on replacing all of them, as several have rust, but that's a good idea on the lapping of the seats.

                        Doc.
                        The two in the pump bottoms should be inlet checks,gravity operated,the two between the handles will be outlet checks and spring loaded?And the one under the handwheel will be the return block.

                        The two inlets and the return block will be the most important.

                        Did you get into the cylinder yet?
                        I just need one more tool,just one!

                        Comment


                        • #13
                          Originally posted by Doc Nickel
                          The seller said that what he'd intended to do, but before he could, he got a good deal on a 50-ton Dake.

                          It's always possible, of course, but I'd prefer the manual pump for the time being. (That and I'd rather not blow $300+ on an electric power pack at the moment. )

                          Doc.
                          With as big as that HV pump is,it will prbably out pace the porta power pump anyway.
                          I just need one more tool,just one!

                          Comment


                          • #14
                            One other bit: On the pump ram, there's a snap ring toward the lower end, just above the tapered portion.



                            This snap ring, and it's mating groove, show signs of abuse- as if the ram had been raised to the max upward stroke, regularly and forcefully. The clip is bent slightly concave, and the groove's edge is peened slightly.

                            However, the underside of the threaded cap shows no damage or wear at all. If the damage on the shaft came from being raised rapidly and forcefully, it must have hit something besides the cap.

                            What that other thing could have been is beyond me, though.

                            An alternate theory is that the damage came when someone tried to remove the now-missing piston. The nuts, threads and disc at the end, however, show no damage, so... ?

                            Doc.
                            Doc's Machine. (Probably not what you expect.)

                            Comment


                            • #15
                              You got me,that setup is a bit unusual.
                              I just need one more tool,just one!

                              Comment

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