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live center won't eject from tailstock

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  • live center won't eject from tailstock

    I have a 9"SB lathe, the live center I have will not eject when I retract the tailstock ram. It measures approximately 2-3/4"from rear of live center head to end of the morse #2 taper. My tailstock drill chuck measures approximately 3-1/4" from rear of the drill chuck body to the end of the morse taper that ends with a tang and easily ejects on retraction of the ram. The live center has 5/16"X1-1/2" non threaded recess in the rear. Any ideas how I could add a tang to the live center. Also how does the tang facilitate the ejection? Thanks Paul

  • #2
    The live center I use on my SB9 was similar. It isn't quite long enough on the end of the taper to eject.

    The measurement that matters is the length from the exposed part of the taper where it just shows from the barrel when seated to the tail end of the taper. When you wind in the barrel the tail of the taper should contact the screw operated by the handwheel. This pushes the taper out of the barrel.

    Put in the drill chuck and mark up the taper where it shows at the edge of the barrel with a sharpie. Do the same for the live center and compare to see how much shorter the taper is on the center. Then machine a brass or aluminum dowel to a light press fit in the hole in the tail end of the center taper and make the length required to match the length of the taper on the drill chuck. Press it in. Problem solved.
    Free software for calculating bolt circles and similar: Click Here


    • #3
      It facilitates because it sticks out... the ram screw hits it.

      So make your center longer.... many have a screw hole down the middle of the taper, so if there were a threaded hole...screwing a screw into that hole would be one way. Or putting in a piece of rod, if it isn't threaded like yours.

      If its solid, drilling your own hole and threading it would give the same capability.

      Keep eye on ball.
      Hashim Khan


      • #4
        Hah. Beat ya.
        Free software for calculating bolt circles and similar: Click Here


        • #5
          Yeah, I had me one of them. Previous owner couldn't figure out how to get it out of the spindle; maybe that's why I got that lathe so cheap, huh? Like the other guys said, just give it a longer tail and it'll be good as ever. I drilled and tapped the end of the taper, and made a new 'button' for its butt plug. Overlong to start, then shortened until I liked the ejection spot.
          I'm here hoping to advancify my smartitude.


          • #6
            Mean time, if it is still stuck in there and you want to get it out, I've used a strap wrench and slightly rotated the center to get it out of my sb 9" tailstock.


            • #7

              A 1/2" diameter ball from a bearing and two drops of locktite fixed my live center just fine. No machining involved.


              • #8
                If we resolve all our problems without machining were will we be?? sitting with a pile of redundant old iron that's where.I say make your own ball bearings then fix it Alistair p.s theres got to be machining involved on this forum
                Please excuse my typing as I have a form of parkinsons disease


                • #9
                  I had the opposite problem with a jacobs chuck that I had mounted on an enco 3mt arbor. I was losing about 3/4 of an inch of travel from my tailstock because I couldn't retract it all of the way or it would eject from the tailstock. I compared it to the shank on my center and made a mark and took a 4 inch cutoff wheel to it. Now it still ejects and I have gained my tailstock travel back.
                  Jonathan P.


                  • #10
                    if still stuck, also have used a pickle fork, or ball joint spitter, if it will fit, place behind live center collar, front of tailstock nose and just gently lever it out. wont work for dead center unless you clamp a collar or vice grip on it or something. works in a "pinch"
                    "Good judgment comes from experience, and often experience comes from bad judgment" R.M.Brown

                    My shop tour


                    • #11
                      live center won't eject

                      Thanks for the prompt and informative replies. I will try your suggestions. Paul


                      • #12
                        To remove a stuck center from the SB9 tailstock take a wrench and unwind the cap on the tailstock that the handwheel is attached to the stock with. Unwind the lead screw and remove. This takes all of 30 seconds. Use a brass or aluminum dowel to punch out the center. Note, tighten the barrel lock first. Replace the lead screw and handwheel. Total time less than 2 minutes if you are slow.
                        Free software for calculating bolt circles and similar: Click Here


                        • #13
                          On my SB9 all I have to do is keep turning the handwheel and the ram comes right out. I have a drill chuck arbor from The Little Machine shop, and it seems to be made to work on the small Asian machines. To short for the SB.

                          I have a piece of brass rod that fits the threaded hole and a light bounce on the bench pops the arbor out.

                          A note; The Little Machine Shop sells a real nice MT3 drawbar type arbor with a 3/4 16 thread on it. It lets me use all my small Taig chucks and collets.


                          • #14
                            I have some slight stickiness with a mt2 to jt3 (for my big drill chuck) generic adapter which may be a similar situation. The live center I bought with the mt2 that the little lathe of mine (enco 9"x20" bench lathe) has on the tail end also sticks on the taper some times.

                            Regardless, thats what my big rubber mallet is mostly used for. Just put a gloved hand in front to "catch" the live center, taper adapter, drill chuck or whatever because sometimes they really fly out with even just a gentle tap.

                            I forget but some of my tailstock adapters or inserts will "self eject" if you feed the tailstock all the way out. But then its a pain getting it back in. Easier by far to just tap em out with a rubber hammer.
                            “It was not til Leibniz and Newton, by the discovery of the differential calculus, had dispelled the ancient darkness which enveloped the conception of the infinite, and had clearly established the conception of the continuous and continuous change, that a full and productive application of the newly found mechanical conceptions made any progressâ€‌

                            Hermann von Helmholtz (1821-1894)