lathe turning taper toward headstock

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lathe turning taper toward headstock

Home Forums General Questions lathe turning taper toward headstock

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  • #139257
    mike mcdermid
    Participant
      @mikemcdermid41977

      Lathe has developed a habit of turning tapers

      smaller at headstock end ,it did always cut 1 thou or so over 6 inch but was never bothered ,this seems to have grown to about 5 thou now over 3inches

      doesnt matter wether using tailstock or not taper is the same which rules out the tailstock, in fact i can get a good result by setting over the tailstock to eliminate the taper

      however its not the best option

      any ideas

      no crashes or bangs and wallops of late

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      #23042
      mike mcdermid
      Participant
        @mikemcdermid41977
        #139259
        Nobby
        Participant
          @nobby

          Hi Mike & Guys
          What lathe is it ? are the bearing in the headstock adjusted ok ? if the job is held in a 3 jaw chuck the jaws may be worn at the front allowing the bar you are turning to push away. By the way Happy New Year to you & all the Guys on this forum
          Regards Nobby

           

          Edited By Nobby on 31/12/2013 18:57:22

          #139261
          Thor 🇳🇴
          Participant
            @thor

            Hi Mike,

            As Nobby says, has anything been done to the lathe? A wooden stand will not be as stable as a steel stand, what kind of stand do you have? Have you read Harold Hall's description on Lathe setup, turning paralell etc.?

            Regards Thor

            #139262
            mechman48
            Participant
              @mechman48

              Happy New Year to all the guys on the forum.

              George

              #139270
              mike mcdermid
              Participant
                @mikemcdermid41977

                hi chaps its a boxford 280 industrial

                brand new d1-3 chuck to be honest i had not noticed problems as i was using a 4 jaw and clocking everything

                that got tiresome

                spindle taper clocks at 0 if i put my finest clock on it and i probably am not as good as the clock

                using a cheaper clock

                i get runout on diameter of the chuck is less than 1/2 a thou

                worst on face less than 1/2 a thou and if i put a

                piece of bar in the chuck is 2 thou concentricity anything tighter i switch to the 4 jaw

                if i shift the tailstock i can get ban on diameter over the length of 3"

                even if i pu the old chuck on i get similar taper towards headstock

                #139285
                Emgee
                Participant
                  @emgee

                  HiMike

                  Surprised you have that problem with such a lathe. Just ask if the taper on spindle and in chuck are absolutely clean, also of course the mating faces of chuck and spindle.

                  Is it better by using a particular jaw for tightening ?

                  Rgds, Emgee

                  #139291
                  S.D.L.
                  Participant
                    @s-d-l
                    Posted by mike mcdermid on 31/12/2013 19:40:02:

                    hi chaps its a boxford 280

                    i get runout on diameter of the chuck is less than 1/2 a thou

                    worst on face less than 1/2 a thou and if i put a

                    piece of bar in the chuck is 2 thou concentricity anything tighter i switch to the 4 jaw

                    if i shift the tailstock i can get ban on diameter over the length of 3"

                    even if i pu the old chuck on i get similar taper towards headstock

                    What make chuck is it?

                    if you put a true cylinder in the chuck (bit of silver steel) what is the runout along the bar to that you know is true?

                    ie are the jaws eccentric to the body of the chuck?

                    Steve

                    #139297
                    mike mcdermid
                    Participant
                      @mikemcdermid41977

                      It’s a bison 125 mm
                      The spindle is spotless as is the seat
                      Concentricity on a ground 1 inch bar is about 2 thou over a foot

                      Can’t figure it as the headstock sits on a vee and the bolts are still tight

                      Edited By mike mcdermid on 31/12/2013 22:55:28

                      #139303
                      blowlamp
                      Participant
                        @blowlamp

                        Is this with carbide tooling?

                        If so, grind up a very sharp HSS tool and try that on some brass or aluminium.

                        Martin.

                        #139307
                        Nobby
                        Participant
                          @nobby

                          Hi Mike
                          From you first post it seems as if you have done something different lately have you moved it ? is there a heat source you have put next to it . or another heavy machine next to it
                          Nobby

                          #139311
                          Ady1
                          Participant
                            @ady1

                            Any play on the saddle etc ?

                            Lock it to the carriage.

                            Then try locking the carriage at various points along your bar

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