Cutting worms with less tpi than lead screw

Advert

Cutting worms with less tpi than lead screw

Home Forums Workshop Techniques Cutting worms with less tpi than lead screw

Viewing 10 posts - 1 through 10 (of 10 total)
  • Author
    Posts
  • #234370
    Rufus Roughcut
    Participant
      @rufusroughcut

      Hi Gents

      Recently aimed to make a replacement 5 tpi worm shaft for a mini cultivator on myford ML7/ ML10 without gearbox as the lead screw is 8 tpi has anyone achieved less than 8tpi lefthand worm shaft on these or could anyone offer suggestions

      Rufus

      Advert
      #15845
      Rufus Roughcut
      Participant
        @rufusroughcut
        #234375
        Michael Gilligan
        Participant
          @michaelgilligan61133

          No practical experience; but I believe the preferred method is 'thread milling'

          A milling spindle replaces the normal lathe tool, and away you go.

          MichaelG.

          #234384
          Bazyle
          Participant
            @bazyle

            Common solution is to set up as normal but use the leadscrew handle to provide the power. I believe the ML10 has a handle….

            #234431
            John P
            Participant
              @johnp77052

              Hi Rufus
              Seen here in photo cutting a 5 start worm ,i think it
              is .8 mod as it was done about 6 years ago , if
              so the pitch is just under 1/2 inch ie 2 tpi.
              See article in MEW 241.
              Photo in album rotary table.

              John

              #234435
              Jon Gibbs
              Participant
                @jongibbs59756
                Posted by Bazyle on 12/04/2016 22:34:04:

                Common solution is to set up as normal but use the leadscrew handle to provide the power. I believe the ML10 has a handle….

                Bazyle,

                Do you mean a mandrel handle?

                Otherwise how do you guarantee 5TPI?

                [Edit: Oh, I think I see now – Doohh. Is the idea to drive the spindle from the leadscrew? – thanks]

                Jon

                Edited By Jon Gibbs on 13/04/2016 10:03:24

                #234443
                Ajohnw
                Participant
                  @ajohnw51620

                  5 tpi from an 8 tpi leadscrew should be ok it's not pushing things all that far. Just run the lathe at min speed and check how fast the carriage moves to be sure you are comfortable with it or turn said leadscrew or the lathe spindle with a handle.

                  If you were making lots and lots of them things will wear out more quickly than more normal pitches but you aren't. For one offs the main problem with this sort of thing can be the speed the carriage moves at. I recollect Rod cutting helical gears like this with a much coarser pitch so had to use a handle.

                  John

                  #234461
                  Russell Eberhardt
                  Participant
                    @russelleberhardt48058

                    I've cut 1" pitch oil grooves by use of a leadscrew handle driving the spindle through the change wheels. More than one way to skin a cat!

                    Russell.

                    #234472
                    Roderick Jenkins
                    Participant
                      @roderickjenkins93242
                      Posted by Ajohnw on 13/04/2016 10:23:59: I recollect Rod cutting helical gears like this with a much coarser pitch so had to use a handle.

                      Indeed. That was using a milling spindle powered gear cutter – analogous to thread milling. Driving a single point threading tool from the leadscrew handwheel is probably going to be difficult since the mechanical advantage is all the wrong way. Personally, I'd do as John suggests and set it up in the conventional way to cut 5tpi – just be aware of the issues, take it slowly and carefully and see if it works. A hand crank on the lathe mandrel is always a useful thing to have and I often use it for thread cutting, it will give you some feedback as to how the job is going before anything breaks!

                      HTH,

                      Rod

                      Edited By Roderick Jenkins on 13/04/2016 13:19:28

                      #234495
                      Ajohnw
                      Participant
                        @ajohnw51620

                        blush I suppose I should have added set the compound slide at the correct angle so that this can be used to set the depth of cut and take cuts that are well within the capability of the machine especially as the "thread" get deeper – just as anyone would when cutting coarse threads. Or may quickly realise that they should have done it this way handle or not.

                        John

                      Viewing 10 posts - 1 through 10 (of 10 total)
                      • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

                      Advert

                      Latest Replies

                      Home Forums Workshop Techniques Topics

                      Viewing 25 topics - 1 through 25 (of 25 total)
                      Viewing 25 topics - 1 through 25 (of 25 total)

                      View full reply list.

                      Advert

                      Newsletter Sign-up