Practical single point threading dia limitations
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    Default Practical single point threading dia limitations

    Looking for guidance and past experience regarding smallest thread size for practical lathe single pointing using both HSS and carbide tooling. Always appreciated.

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    Depends a lot on the material. I can tell you from experience that 0-80 in 0.9999 silver has a low probability of success.

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    Quote Originally Posted by mnl View Post
    Depends a lot on the material. I can tell you from experience that 0-80 in 0.9999 silver has a low probability of success.
    My dad single pointed an 0-80 on a 16" lathe on a bet.

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    Quote Originally Posted by jlakes85 View Post
    Looking for guidance and past experience regarding smallest thread size for practical lathe single pointing using both HSS and carbide tooling. Always appreciated.
    Well, "practical lathe single pointing" is kind of a broad expression. What lathe and what material and male or female? My Levin and Derbyshire lathes can make watch-size male threads with pitch as fine as 200 TPI. I have only gone down to .060-90 threads to make a knurled head steel thumb screw on a Levin, but I could have gone smaller if I really had to.

    OEM screwcutting attachments are rare, so I made my own back in 1982.

    Larry

    16-tpi-40t-int-front.jpglevin-screw-cutting-lathe-1.jpgtool-bit-60-deg-brass-2.jpgvanice-s.c.-attachment-captioned.jpg

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    Quote Originally Posted by SIP6A View Post
    My dad single pointed an 0-80 on a 16" lathe on a bet.
    Oh YEAH? Well my dad could do 00-00100 on a 28" lathe

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    OK, Johnny.

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    Quote Originally Posted by HuFlungDung View Post
    Oh YEAH? Well my dad could do 00-00100 on a 28" lathe
    hell I cut a M1 on a 6m vertical...

    hand fed , by eye usinga tool i lapped on the more abrasive parts of my underpants!.

    (then i woke up) ;-)

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    Quote Originally Posted by jlakes85 View Post
    Looking for guidance and past experience regarding smallest thread size for practical lathe single pointing using both HSS and carbide tooling. Always appreciated.
    5/8" or 3/4" and up, any common thread and form.

    Anything smaller, one uses geometric dies for economy of production, hand dies in a well-made holder where the lathe is an alignment jig as much as a power source. Some lathes, power is OFF, and one tommy-bars them.

    Decent dies - held in proper alignment - hit spec.

    US spec, Metric spec, Whitworth spec, BSA spec, archaic TPI and form...wotever the die is. Matters not a wit what race or tribe the leadscrew is.

    And they hit it first time, every time.

    Usually in one pass, not 'many'.

    Just because one CAN single-point down to silly-small doesn't mean it makes good sense in time or money, even if it is the retaining nut that secures a sheave or gear onto the end of a costly 100 HP DC motor armature shaft.

    Dick-swinging is a separate project. MAKING a good geometric die, f'rinstance.


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    I am interested in answers as well.

    I have no experience making really fine threads, but wish to, on good cnc equipment, in steel.
    Thus, any practical experience in steel is valued and appreciated.

    Hoping to do approx 0.1-0.2 mm rise threads, or about 80-125 tpi.
    And in trapezoidal, aka acme.
    Micrometer threads.

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    Monarchist wrote:
    "5/8" or 3/4" and up, any common thread and form...
    Anything smaller, one uses geometric dies for economy of production, hand dies in a well-made holder ... Just because one CAN single-point down to silly-small doesn't mean it makes good sense in time or money, even if it is the retaining nut that secures a sheave or gear onto the end of a costly 100 HP DC motor armature shaft."

    You're kidding...right??
    Please tell me you're kidding.
    If you're not...I've got pictures to show you and a small challenge for you.


    Cheers
    Marcus
    Implant Mechanix • Design & Innovation > HOME
    www.vancouverwireedm.com

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    Quote Originally Posted by hanermo View Post
    I am interested in answers as well.

    I have no experience making really fine threads, but wish to, on good cnc equipment, in steel.
    Thus, any practical experience in steel is valued and appreciated.

    Hoping to do approx 0.1-0.2 mm rise threads, or about 80-125 tpi.
    And in trapezoidal, aka acme.
    Micrometer threads.
    All that has learning curves.

    USUALLY, there are specialist makers who not only do threaded goods better than most, they've driven the unit costs down. Ballscrews and common Acme forms for everything from uber-precise machinery leads to not-so-critical vise clamping or automotive lifts are good examples. So are fasteners for watches and fine instruments.

    Makes more sense to purchase, UNLESS.. the threaded portion is so integral to some major component, it cannot be readily hived-off.

    Your micrometer screws probably can be severed, sent to an already-established specialist with a hundred and more years 'head start' at the game.

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    Makes more sense to make them -
    I am interested in making them -
    I do not much care what it costs to start.

    I am not interested in making one gizmo with one screw.
    Already have samples of differential screws from thorlabs at 70$ each, 210$ for 3, that is just an example.
    And custom dies and taps.

    As you said, one needs to get good at it, and this will have a ramp/slope/costs.
    Fair enough.
    Quote Originally Posted by Monarchist View Post
    All that has learning curves.

    USUALLY, there are specialist makers who not only do threaded goods better than most, they've driven the unit costs down. Ballscrews and common Acme forms for everything from uber-precise machinery leads to not-so-critical vise clamping or automotive lifts are good examples. So are fasteners for watches and fine instruments.

    Makes more sense to purchase, UNLESS.. the threaded portion is so integral to some major component, it cannot be readily hived-off.

    Your micrometer screws probably can be severed, sent to an already-established specialist with a hundred and more years 'head start' at the game.

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    Hi Hanermo:
    Pitches this fine and with the kind of precision you sound like you need are likely going to best be ground rather than single point turned.
    I'd be looking for a turnkey vendor of equipment that can do this, and will walk you through all you need for a complete solution including whatever metrology makes sense for what you want to do.

    Bill is quite right in that there is a ton of experience out there that's worth tapping into...I'd be talking to people like Drake:
    Here's a link:
    GS:TEM-1 External Thread Grinder | Drake Manufacturing Services Co., LLC

    Cheers

    Marcus
    Implant Mechanix • Design & Innovation > HOME
    www.vancouverwireedm.com

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    Quote Originally Posted by SIP6A View Post
    My dad single pointed an 0-80 on a 16" lathe on a bet.
    It wasn't the 0-80, 000-120 was not too hard on that lathe, it was the 0.9999 silver. It was just too soft, and while we probably could have figured out how to do it, the material was so expensive it wasn't practical to practice very much.

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    Quote Originally Posted by mnl View Post
    It wasn't the 0-80, 000-120 was not too hard on that lathe, it was the 0.9999 silver. It was just too soft, and while we probably could have figured out how to do it, the material was so expensive it wasn't practical to practice very much.
    Silver is not even a 'noble' metal, and is dirt-cheap compared to many other materials, 'noble' or merely exotic.

    As to 'how'? 'Fine' Silver swages and polishes beautifully. Also electroforms with superb accuracy.

    OTOH, it won't HOLD anything much.

    So ... other than fooling eye or camera, which could be done with flash plating?

    What would be the point?

    May as well try to make split-lockwashers out of Osmium or Belleville springs out of Thorium for all the utility one could get out of the exercise.

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    Smallest to date was small lead screw 5/32dia x 1ft long sq thd 16tpi. Mat bms,machine 16"Sidney!

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    finest tap and nuts i made were 127 tpi and i used front of cutter not top. it was more a single point knurling operation forming threads.
    .
    i used a anti seez graphite lubricant. i do not have any trouble making threads.
    .
    forming threads goes back to Maudslay and the first lathes

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    I've done very nice M0.9x0.16 threads in 303 stainless up to an inch or more long. The trick is the follower rest. I did them on a small U.S. made machine that can't be mentioned here. People trying it on "real" machines never had much success at it. We spent lots of time and money trying to have it rolled, but that didn't work either. Ultimately quantity production went to Japan where there are companies that specialize in this sort of thing. I thought mine were pretty good, but theirs were near perfect and at about 1/100 the price.

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    with 127 tpi i always had to have a split nut that could be tightened to squeeze threads a bit. might have .005 thread enagement.
    .
    i also left anti seez compound on threads. threads are fine enough it could be mistaken for a moderately rough turned finish. if screw is steel and nut is brass it will conform and threads match as its worked back and forth

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    Quote Originally Posted by DMF_TomB View Post
    forming threads goes back to Maudslay and the first lathes
    It was already old before he ever enjoyed his first teat-lock.

    He just helped make it repeatable and affordable.

    "Standard", OTOH, remained more elusive than cooperative teats for quite a while, though!



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