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Thread: Swing threading tool

  1. #1
    Join Date
    Mar 2001
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    Default Swing threading tool

    [EDIT] This idea was originally by Mike Cox, then picked up by John Moore, John did give credit to Mike Cox, I missed it, my mistake.

    First off let me give credit where it is due as the design concept came from John Moore over in the UK, my only input was suggesting the use of a key to locate the tool.

    John's initial design was for a swinging holder to hold a replaceable brazed tip tool.

    I cheated and used the tool as the swinging element.

    I have some spare blank holders for my quick change system on the lathe, some full ones and some narrow ones for things like parting blade holders.



    The one in the foreground was made as a threading tool and it works but in practice if you need a tailstock centre you can't get close enough so I was going to use John's design and this threading tool but then after a sort out I found a big old brazed tip tool and decided to use this as both the tool and the swinging holder.

    The tool was accurately marked out for the pivot hole and then drilled thru into the holder and tapped.



    It was then turned upside down and again accurately marked out for the location key to fit.



    The tool was bored out and a brass bush fitted that extended by about 5 thou and a keep plate was screwed to the bottom, again with a 5 thou shim fitted whilst drilling and tapping the holes.



    End of first post because of 4 picture limit, please don't reply until second post appears to keep continuity.

    .
    Last edited by John Stevenson; 12-23-2009 at 07:00 PM. Reason: Give credit to Mike Cox.
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  2. #2
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    Default

    Second post.

    Two more pics of the finished tool, this took literally 1 1/2 hours to make but I did have the holder already done, no drawings, just typical weld it where it touches and no microns were harmed in the making of this tool.







    In use you turn a run out groove at the end of the thread and when the tool gets into this you just reverse the machine with the cross slide untouched.

    You would think that it would tear the thread but what happens is that it lifts and runs back down the thread out of the cut.
    You can even put the new cut on as you are going backwards !!

    Then select forward and do the next cut.

    Video here. http://www.youtube.com/watch?v=2F_AVx_JRlE&feature=related

    And shot of the finished thread .



    This was 2mm pitch, [ about 13 tpi ] cut at 135 rpm.

    OK done now, flames, bricks etc but it was the fastest thread I have ever cut.

    .
    Last edited by John Stevenson; 01-14-2011 at 02:57 PM.
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  3. #3
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    Default

    Very cool, I like how you left it free to swing up a LOT, the other tool posted here looked like it would fail to lift up enough on large diamiters with low TPI's

    Crazy backwards QCTP system.

  4. #4
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    Default

    Terrific! My only question is "Why doesn't everybody do it that way?"

    That's the same question I asked when I first encountered the Hardinge HLV threading system. The instructions for my Hardinge clone say "please do not thread above 1000 RPM." At first I thought it was a bit silly, but once you have a nice mechanical system like that, you can really rip.
    Cheers,

    Frank Ford
    HomeShopTech

  5. #5
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    That is just soooo kewl, I love it!

    The brazed tip tool -- did you get the thread profile by regrinding a common existing profile (using carefully marked out dimensions of course!!) or -- how did you get it?
    If everything seems to be going well, you have obviously overlooked something........

  6. #6
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    Austin, Texas
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    Default

    Quote Originally Posted by Frank Ford
    Terrific! My only question is "Why doesn't everybody do it that way?"
    Well... this is Bogstandard's design, that we discussed last week -- he was trying to replicate Martin Cleeves' swing toolholder with a much simpler design:




    With Bogstandard's design, you have to reverse the spindle to lift the threading tool out of the cut. A bit of a kludge, IMHO.
    The Hardinge flying dog clutch and the retracting toolpost is the ultimate answer, but how many actually have that?

    John's thread looks superb, obviously, but John could cut a good thread with a plastic fork
    Last edited by lazlo; 12-23-2009 at 10:32 AM.
    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

  7. #7
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    No criticism from me, but I am curious how well it does with a left hand thread. I realize that is the purpose of the lug and slot so left hand threading was a design consideration.

    What is the concern level for trapping swarf under the cutter?

  8. #8
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    Aug 2004
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    Default

    I really like this setup. Who wouldn't? My question is what is the best method of adding a responsive brake to a lathe without one?
    Paul

  9. #9
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    Milwaukee
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    Default

    Quote Originally Posted by dp
    No criticism from me, but I am curious how well it does with a left hand thread. I realize that is the purpose of the lug and slot so left hand threading was a design consideration.

    What is the concern level for trapping swarf under the cutter?
    Since the key/lug in the bottom takes up the cutting force equally in each direction, I would think that LH threads would work just as well. A piece of carboard or the back of a note tablet with an X cut into it, placed over the bit and bent back over the top of the assembly would do a pretty good job of keeping the chips out of the works.

  10. #10
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    I wonder would it work without the key?
    "...do you not think you have enough machines?"

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