Need quick info" what TIR can I hold with a rigid,tailstock mounted thread die holder
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    Default Need quick info" what TIR can I hold with a rigid,tailstock mounted thread die holder

    So my 60's era Clausing lathe is in immaculate shape and holds truly surprising tolerances. But she don't cut metric wrinkles.


    I'm coming up with a long term solution. But I need the cut metric threads....about .75" thread length on the shank of a high precision shaft...NOW.

    I really need the short section of threads threads to be within .00035 TIR. I might could live with .0005" but that is absolute max and unwelcome.

    Is their a snow ball's chance I could hold this with a rigid, Morse taper thread die holder?

    I'm pretty sure...no way! But they say it never hurts to ask.

    Much thanks.
    MG

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    If these threads are bearing down on a shoulder that surface will have a much greater influence on the fitment of the two mating pieces instead of the thread itself.

    I think you would be lucky to hold a few thou with your setup and your biggest issue will be the fit of the threads- dies are not known for their precision adjustability.

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    Get yourself a set of metric conversion gears.

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    Your doing it wrong....yet again....

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    Quote Originally Posted by digger doug View Post
    Your doing it wrong....yet again....
    You're a very sweet man.

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    Quote Originally Posted by Limy Sami View Post
    Get yourself a set of metric conversion gears.

    That is in-process. Thanks.

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    Quote Originally Posted by MonCeret Gunsmit View Post
    You're a very sweet man.

    Yeah. Helpful too, as usual.

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    How many do you need to do? If one, ( or low numbers) you could try to put a generous taper on the end of unthreaded stud and carefully start it up in there by hand. Depending on the symmetry of the die, and the care taken starting it, it might be possible to get there. I’d imagine it might take a few tries to hit that runout, if it’s doable at all, though. Good luck!

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    I personally believe that .0005" TIR with a die is impossible. I've been wrong before, though. And not too long ago, either.

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    Quote Originally Posted by Gordon Heaton View Post
    I personally believe that .0005" TIR with a die is impossible. I've been wrong before, though. And not too long ago, either.
    Oh... I mis-read that, half a thou.. not 3-5 thou.. well that’s a different kettle of fish.
    No, absolutely not impossible, but it would be a statistical question, out of X tries, at say .003 standard deviation how many would fall inside .0003? How many would you need to do on average to get that result?

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    Quote Originally Posted by cyanidekid View Post
    Oh... I mis-read that, half a thou.. not 3-5 thou.. well that’s a different kettle of fish.
    No, absolutely not impossible, but it would be a statistical question, out of X tries, at say .003 standard deviation how many would fall inside .0003? How many would you need to do on average to get that result?
    More importantly what application requires it? There is 10x+ the clearance between mating threads anyways.

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    Classic question I know...but how's the customer going to measure this?

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    Quote Originally Posted by LKeithR View Post
    Classic question I know...but how's the customer going to measure this?
    Judging by OPs name, if they can shoot the wings off a gnat at 100 yards. More generally, if the barrel is still there after the second shot.

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    Quote Originally Posted by MonCeret Gunsmit View Post
    So my 60's era Clausing lathe is in immaculate shape and holds truly surprising tolerances. But she don't cut metric wrinkles.


    I'm coming up with a long term solution. But I need the cut metric threads....about .75" thread length on the shank of a high precision shaft...NOW.

    I really need the short section of threads threads to be within .00035 TIR. I might could live with .0005" but that is absolute max and unwelcome.

    Is their a snow ball's chance I could hold this with a rigid, Morse taper thread die holder?

    I'm pretty sure...no way! But they say it never hurts to ask.

    Much thanks.
    MG
    Cutting threads on a howa? I think you could get away with using a die. Now if you did that to my barrel that I paid you to install I’d want my money back and take my barrel out of your hands as fast as possible.
    If you are in a hurry look on Craigslist for a lathe with metric gears and go pick it up for $2000 and then you won’t have this problem again.

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    Thanks again everyone. Talked the customer into a SAE thread! Still working on the change gears for future metric thread scenarios.


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