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Myford Spindle Thread?

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  • Myford Spindle Thread?

    Hi Folks,

    Could some kind person tell me the core diameter of the Myford 1 1/8" spindle thread?

    I need to make an internal thread for an adaptor.



  • #2
    An easy way to determine hole size for tapping or threading Imperial threads is to divide 1 by threads per inch and subtract from the major diameter.

    If pitch is 8; 1/8=0.125", hole diameter is 1.00".

    With Metric threads, simply subtract pitch from diameter.

    I don't know the Myford pitch, except that it is a non-standard. Guy Lautard was selling a tap with the Myford pitch for making accessories.
    Jim H.


    • #3
      Thanks JC,

      That's brilliant!



      • #4
        According to Guy Lautard
        Myfords made from 1946-2000
        had a 1-1/8" x 12 TPI thread and it was a 55 deg included angle (British Standard Whitworth) It was a RH thread. I would suggest if you have any other chucks, faceplates etc. for this lathe just measure
        what they was bored to (I.D.) and duplicate.
        I also would using 3 drill shanks as wires
        measure my spindle and make a threaded gage
        to duplicate the spindle so when you bore and thread a new casting you will have a way of knowing if it will go onto yor spindle.


        [This message has been edited by GRH (edited 08-27-2005).]


        • #5
          Thanks GRH, I'll do that.

          It's an unusual job, I have a Vertex dividing head with a Myord sized spindle but I have a spare 4" Warco chuck!

          So I am attempting to make a bush with a Myford 1 1/8" centre thread and a Warco outside thread as an adaptor...

          A new chuck is just too expensive.8-((




          • #6
            Would it not be a better solution to make a new back plate for the chuck or is the chuck used on other equipment??????
            How do you propose to remove the adapter from the chuck??????
            A couple of things to consider.


            • #7
              Hi Graeme,

              Yeah, I did think of the new backplate.

              I did get a blank cast iron one threaded with the myford thread but I wasn't sure that I could get it running correctly enough.

              Then I decided that to get it running really true I'd need a myford spigot to hold it first.

              That led me to the idea that if I could make a spigot with a myford thread then I could just as easily make a theaded adaptor which hopefully would have both of the threads fully parallel as they would both be turned in the same sitting. 8-)

              The back plate on the chuck can then stay on the old chuck and the adapter screwed in. Then if I need to use the chuck on the other smaller lathe I can just remove the adaptor!

              Well that's the plan, wether it works well enough I'll have to see.....

              Either way it's good practice for turning internal and external threads. <g>




              • #8

                Can a Limey Bastard copme in?

                The Vertex dividing head in the Uk is sold with a Myford "nose". Got one!
                However, it comes with a faceplate which will take a lathe chuck.

                One firm sells chucks to go with the Vertex set up.

                Again, part machined Myford backplates are available from many UK stockists.




                • #9
                  Hi Norman,

                  Thanks for your input.

                  After an abortive attempt to make a reducing bush I did indeed manage to make an arbor with the Myford thread then turned the supplied face plate to fit my Warco 4" chuck!

                  So i got there in the end thanks to all the folks help...




                  • #10

                    Sorry, Arnak- I didn't reckon that you were from the Principality.

                    I could have probably given you a more 'local' answer.

                    Something says to me that this Myford thread isn't quite the "bastard" thread which most of us suppose.
                    Instead of doing it at 55 degrees- why not assume that it is 60.

                    Now start thinking laterally.
                    So this is a SAE Fine but with a Whitworth 55.

                    Following on with a bit of lateral thought, who the hell cares about the thread?
                    It's the register that matters.
                    That is a straight inch and a quarter for 7- 16ths. The nose- before we start fiddling is an inch and 5/8ths and 3/16ths.

                    Amazingly simple- but I have never seen the relationship in print before.