Dead Centres?

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Dead Centres?

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Viewing 11 posts - 1 through 11 (of 11 total)
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  • #815183
    Bo’sun
    Participant
      @bosun58570

      I’ve been searching for No.2 MT dead and half centres with either a tang or drawbar thread.  And yes, without success.  Do such items exist?

      I ask, because I’ve just fitted a DRO to my lathe tailstock utilising a 10mm wide clamp around the quill.  I’m still able to eject any tooling which has a tang, but without a tang, the clamp prevents the quill retracting far enough to allow the pin to eject the tooling.  I could try a thinner clamp, but I already have some 10mm thick material.  Even so, things would still be quite close.

      A drawbar thread would allow me to add a stud, or even make a threaded tang.  I’ve seen a few proprietary threaded tangs, but they seem quite costly for what they are and look easy enough to make.

      I’ve considered extending the ejector pin, but would rather not lose any of the already scant quill travel (around 60mm).

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      #815195
      JasonB
      Moderator
        @jasonb

        JBWeld a 10mm thick disc of metal to the end of your CTR.

        #815198
        John Haine
        Participant
          @johnhaine32865

          You can get “blank” MT tapers which are unmachined and have a drawbar thread.  Easy enough to turn a 60 degree point on it and add a bit of studding at the ejection end.  That way you know that the centre is concentric.

          #815199
          Bazyle
          Participant
            @bazyle

            Measure the distance shortfall eg with bit of bluetak on end of arbor. Pop one of more ball bearings to make up the length into the taper before inserting the arbor. The reason for using BBs is they roll back out when done.

            #815213
            Martin Connelly
            Participant
              @martinconnelly55370

              I have bought some with a parallel section near the point. You can grip it in the lathe and drill and tap M6 or 1/4″ and put a bit of screwed rod in it. The shanks are easy to drill and tap, they are not hardened. Found some like this on Ebay just looking for M2 dead centre. They are easy to spot from the pictures.

              Martin C

              #815214
              bernard towers
              Participant
                @bernardtowers37738

                As Martin says but turn the parallel section yourself, or use aNo1 MT centre in a 2 to1 adaptor with a tang!!!!

                #815237
                samuel heywood
                Participant
                  @samuelheywood23031
                  On bernard towers Said:

                  As Martin says but turn the parallel section yourself, or use aNo1 MT centre in a 2 to1 adaptor with a tang!!!!

                  Kinda prefer MT1 dead centres on my mini lathe anyway,shorter, less in the way of tool(post), not sure you really need anything more robust most of the time on small machine?

                  #815244
                  Bo’sun
                  Participant
                    @bosun58570

                    Thanks for the suggestions all.  Plenty to consider.

                    #815251
                    Dave Halford
                    Participant
                      @davehalford22513

                      A blob of weld on the back end of a centre is sometimes enough.

                      #815254
                      JasonB
                      Moderator
                        @jasonb
                        On samuel heywood Said:
                        On bernard towers Said:

                        As Martin says but turn the parallel section yourself, or use aNo1 MT centre in a 2 to1 adaptor with a tang!!!!

                        Kinda prefer MT1 dead centres on my mini lathe anyway,shorter, less in the way of tool(post), not sure you really need anything more robust most of the time on small machine?

                        Kind of depends on the size of teh tailstock taper. If you have got MT2 then you would need to use an adaptor sleeve to fit MT1 which will increase the stickout and risks loosing concentricity.

                        #815256
                        cogdobbler
                        Participant
                          @cogdobbler

                          Be careful before drilling. Some centre shanks are hardened  , some are not. Rub a file over the eris end of your centre to se if it is hard, or soft and drillable. And some are case hardened while others through hardened. If case hardened, you can grind a couple of millimetres off to get through the hard case to the soft, drillable core.

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