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20 ton Hydraulic Press Project

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  • 20 ton Hydraulic Press Project

    This is the 20 ton press I built a few months ago. It was inspired by posts I had read here about using an inverted bottle jack as a ram.

    Because of the four picture limit, it's going to take several posts to fit it all in. So please bear with me.

    I suppose you could say I cheated a bit from the get-go. Rather than build the frame, I used a 55 ton press frame that was given to me [minus the hydraulics].

    For the ram, I bought a $35 20-ton bottle jack.

    First step was to drain the oil and pull it apart. I don't have a big enough monkey wrench for the top nut so I held the nut in a bench vice and unscrewed it from the bottom with a pin spanner (which was made years ago to hold a Husky flywheel).

    My strap wrench wasn't strong enough to remove the cylinder from the base so I had to just work around it. Here, I am drilling the base to accept a pressure gauge.

  • #2
    First an 1/8" hole that went clear under the cylinder, then open the end with an 11/32" drill. Finish off with an 1/8" pipe tap (not shown).

    An intersecting hole was drilled through the bottom of the cylinder. That was not a fun task with the cylinder still in place.

    The reason to open it up in the first place was to add a "straw" to the feed hole so that it won't suck air when inverted. I grabbed a chunk of brake line, beveled the end on a bench grinder, dabbed on bit of LocTite then tapped it into the hole.

    Cleaned it up, put it back together, and filled it with oil. Notice the pipe plug since I don't have a gauge for it yet.


    • #3
      This press features a sliding head so mounting the ram was fairly simple. There is a one inch plate that sits in a track below the top beam. I removed the plate, drilled some holes in the base of the ram, set it on the plate, marked the hole locations with a transfer punch, then drilled them out on the drill press. The holes were tapped to accept some cap screws. I also drilled and tapped a hole for a shoulder bolt which will be the anchor for the lever pivot.

      The head was cut off the shoulder bolt and a cross hole was drilled. Mounting the pivot in front of the pump reverses the motion so that I am pulling the handle rather than pushing. Also notice where I drilled out the "pimple" that originally kept the bar from sliding through the back of the lever, and added a roll pin to the new back to serve the same purpose.

      The screw tip of the ram is peened internally so that it can not be completely unscrewed. I had read where some people would grind the ram where the nut is swaged, in order to disassemble it. I found it much easier to simply unscrew the tip as far as it would go, cut it off, grind a slot in it, then screw it into the ram with a flat blade screwdriver. The ram is deep so the remnant won't interfere with anything screwed into the end.


      • #4
        The idea is to make a new tip for the ram that can be easily removed and faced in the lathe any time it starts to get beveled or mushroomed. I can even make custom tips for particular jobs to rely less on scary spacers.

        I grabbed a steel bar from the scrap bin and faced / chamfered one end.

        The other end was center drilled and turned down for the threads.

        I ground a HSS tool to match the profile of the original threads and got the bar all mounted up in the Atlas. It wasn't until I went to setup the change gear for the 6mm pitch that I realized that I didn't have enough gear bushings. I was nearly ready to throw up my hands and say, "Well, there is nothing I can do until I order that part." Then I noticed that the third bushing simply held an idler gear. There was no need for the special keyed bushing. I dug through my junk box and found the appropriate hardware, then turned an aluminum bushing out of a gate stub. The new hardware would only allow the idler gear to mount in the "back position" so I had to flip the entire gear arrangement front to back, including the "stud gear". It all went together and worked like a charm.

        Chasing the thread was pretty straight forward. It's a metric thread so the half nuts stayed engaged the whole time and the motor was reversed to return the tool for the next cut. The depth was limited to 0.003" per pass. Seriously, even at 0.004" things got pretty scary since it's like threading with a parting tool.


        • #5
          The original screw was really loose so I intentionally made this one larger to try and get a better fit. The first attempt did not fit.

          I put it back in the Atlas, picked up the thread, then peeled off a bit more. Success!


          • #6
            I wanted a permanent handle on the release valve rather than use the end of the jack handle.

            I dug around hoping to find an old spigot handle or something. What I found was an old gate stub that was the right size.

            Just cut it off, drill two holes in it, tap the pin out of the bleed screw, stick the screw in the handle, then tap the pin back in.

            Quick, effective, and free.


            • #7
              I extended the ram, set the whole thing on a bathroom scale and measured how much force was required to retract the ram. It came out to 120 pounds which led me on a futile search to find spring that pull 120 pounds and stretch six inches.

              I eventually switched gears, stepped back and asked the real question. "Why does it take 120 pounds to retract this ram?" The answer of course is that this is a "bargain" priced item and therefor not built correctly. More specifically, the o-ring groove in the nut was not made deep enough so there was excessive friction on the ram.

              The solution was to setup the nut in the four jaw, indicating off of the bore...

              Then turn the groove deeper.

              I wasn't sure how deep to make the groove so I just took a little off at a time. After each cut, put the o-ring in and slide the ram through it. I stopped cutting when it felt right.

              With it all reassembled, it took less than 20 pounds to retract the ram. I had no trouble finding springs that could handle that.

              I also had a happy accident when it was disassembled the last time. I managed to knock over the container of hydraulic oil and make a mess of everything on my work bench. That wasn't the happy part. The happy part was the night and day difference in the pumping action from the replacement hydraulic oil. All I had to substitute it was 15 weight fork oil which was a bit thicker than the original oil. With the original oil it felt like half of the lever travel was used to seat the check valve, probably why some guys recommend mounting little springs under the ball. With the thicker oil, the ram starts moving as soon as you pull the lever, there is no more "slop".


              • #8
                The last piece I had to make was a spring bracket for the ram. This was again made from pure scrapbinium. I drilled and bored a hole in it, then made a small counter bore so it would fit snug around the OD of the ram.

                Final assembly.

                Ram extended.

                That's about it. With one lucky score, $50 out of pocket, and roughly 20 hours of labor, I have a handy addition to the shop.


                • #9
                  Very nice work. Now, crush something for us.


                  • #10
                    Nice build! HF has the air.hydraulic if your arm gets tiredfot $89. I ordered one for mine last night. 20 Ton Air Hydraulic Bottle Jack Item #:95553

                    Looks great!


                    • #11
                      Nice....if the frame is rated at 55 ton how come you didn't get a cylinder to match? Just curious

                      Wish I could luck into "finding" something like that. Been wanting a shop press for years.


                      • #12
                        Originally posted by Robo View Post
                        Nice....if the frame is rated at 55 ton how come you didn't get a cylinder to match? Just curious
                        There are a few reasons. I think the 55-ton rating was a bit optimistic. It may technically be able to hold that much, but I had used this press before it was decommissioned and it didn't seem quite rigid enough to really push it that far. The highest I ever took it was 30 tons and there was quite a bit of spring back when the part popped loose.

                        The most obvious reason is price. A 20 ton bottle jack is much cheaper than a 50 ton. Plus, the bigger it is, the more times you have to pump the handle to get it to move a given distance.

                        For the majority of the work I do, 20 ton is more than enough. If I ever have a steady need for more than that, it would be simple to add a second ram because of the sliding track mount. For one-off jobs I could just go to the place I got the frame from and use their press. They replaced this one with a 75 ton press.

                        Wish I could luck into "finding" something like that. Been wanting a shop press for years.
                        I have been using a cheap Chinese "12 ton" press for over ten years. For most of that time I have had my eye out for a "real" press and was finally lucky enough to be in the right place at the right time. Don't get me wrong though, that cheapy press has served me well. It's paid for itself a hundred times over. If you don't already have one then get one. You will be surprised how much use you will get out of it.


                        • #13
                          Nice - was wondering how you got that cylinder to work upside down,,,

                          my little 12 ton HF just butt's the top of the drive of the bottle jack up against an A-frame whilst the lower part of the jack fits on top of a drive plate with a guided center shaft...


                          • #14
                            That release knob really keeps catching my eye! Kinda mushroomy.

                            I am "needing" a press about now for about 5-6 bearings in my tranny rebuild, but I looked at the Harbor Freight offerings previously and was underwhelmed. I really like that inverted jack you did as opposed to the moving support like the HF uses.


                            • #15
                              Nice job!