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Thread: up side down threading

  1. #1
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    up side down threading

    dit my first barrel with a lefthandholder/insert/neg plate upside down (no place enuff on my lathe do do it from the back side ) at 500 rpm (max speed i can start my lathe in S) and it is so easy and clean and quick i wonder why i dit it not before nearly no thread clean up

    i got a metric lathe and it is a very slow to thread without unlocking the halfnut and returning in low speed ( i now there is a system i can do it but i am not a real fan of to complicated)
    yes i got a recoil lug

    Click image for larger version. 

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  2. #2
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    well done

    Quote Originally Posted by johan teughels View Post
    dit my first barrel with a lefthandholder/insert/neg plate upside down (no place enuff on my lathe do do it from the back side ) at 500 rpm (max speed i can start my lathe in S) and it is so easy and clean and quick i wonder why i dit it not before nearly no thread clean up

    i got a metric lathe and it is a very slow to thread without unlocking the halfnut and returning in low speed ( i now there is a system i can do it but i am not a real fan of to complicated)
    yes i got a recoil lug

    Click image for larger version. 

Name:	E0966332-DB4D-469D-8D6F-60FB8937D58A.jpg 
Views:	302 
Size:	509.3 KB 
ID:	22228

  3. #3
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    Surprised more people donít do it. I learned toward the headstock and am guilty of keeping with that technique, but like threading away. Still feels a little weird to me though

  4. #4
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    Quote Originally Posted by johan teughels View Post
    dit my first barrel with a lefthandholder/insert/neg plate upside down (no place enuff on my lathe do do it from the back side ) at 500 rpm (max speed i can start my lathe in S) and it is so easy and clean and quick i wonder why i dit it not before nearly no thread clean up

    i got a metric lathe and it is a very slow to thread without unlocking the halfnut and returning in low speed ( i now there is a system i can do it but i am not a real fan of to complicated)
    yes i got a recoil lug

    Click image for larger version. 

Name:	E0966332-DB4D-469D-8D6F-60FB8937D58A.jpg 
Views:	302 
Size:	509.3 KB 
ID:	22228
    Did you plunge straight in with the cuts or angle feed 30 degrees to the right?

  5. #5
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    Quote Originally Posted by alinwa View Post
    Did you plunge straight in with the cuts or angle feed 30 degrees to the right?
    Will each way make the same dimension thread?

  6. #6
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    while i was taught to cut from the side, i do straight plunge today.

  7. #7
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    Quote Originally Posted by alinwa View Post
    Did you plunge straight in with the cuts or angle feed 30 degrees to the right?
    straigh in so i can track the depth on my DRO

  8. #8
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    This method wasn't taught because most old lathes had screw on chucks and no reverse spindle rotation.

  9. #9
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    Nothing wrong with upside down threading. The cuts are generally lightbenough as not put much stress on the lower gib plates that keep the carriage from rising up.

    And you are correct. When cutting metric threads on a Lathe to a shoulder with an American lead screw, it is easier since you cannot disengage the half nut.

  10. #10
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    Quote Originally Posted by jackie schmidt View Post
    Nothing wrong with upside down threading. The cuts are generally lightbenough as not put much stress on the lower gib plates that keep the carriage from rising up.

    And you are correct. When cutting metric threads on a Lathe to a shoulder with an American lead screw, it is easier since you cannot disengage the half nut.
    and like always the master got some toughts i never took in concideration but 100%right now i thing about it thx jacky

  11. #11
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    When I thread metric on my lathe, I disengage the half jut just like standard threads, but reverse the spindle and re-engage the halfnut on the same number I was in on its way back and carry the tool back past the tenon for the next cut...it works and I donít have to try and withdraw far enough to clear the shoulder or reverse the lathe immediately. As long as you donít let the thread dial get a revolution off youíre fine.

  12. #12
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    Quote Originally Posted by msalm View Post
    When I thread metric on my lathe, I disengage the half jut just like standard threads, but reverse the spindle and re-engage the halfnut on the same number I was in on its way back and carry the tool back past the tenon for the next cut...it works and I donít have to try and withdraw far enough to clear the shoulder or reverse the lathe immediately. As long as you donít let the thread dial get a revolution off youíre fine.
    This method works great, but as you stated , you have to make sure that you keep the half nut on that same spot on the lead screw or you will never find the lead again. It helps to have a Lathe with a dynamic brake.

  13. #13
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    Quote Originally Posted by sdean View Post
    Will each way make the same dimension thread?
    sdean I don't know what that means? Please rephrase the question? I'm kinda' literal......

  14. #14
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    Quote Originally Posted by alinwa View Post
    sdean I don't know what that means? Please rephrase the question? I'm kinda' literal......
    I just meant to a real machinist. 29 or 30 degrees on the compound is the correct taught way. Is the only difference just cutting with one side of the tool. Is there anything technically wrong with just going straight in?
    Would anyone catch Jackie plunging straight in? 😯

  15. #15
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    I picked up the aloris threading tool #8 http://www.aloris.com/products/threading-holder-8/ on a, albeit expensive, whim,
    and it works great for threading away from the headstock. I produced the best threads I have have made and have no intention of going back to the towards the headstock method. The tool has an HSS bit that is easily ground though I did need to relieve some of the material on the left side of the insert to allow a closer fit to the shoulder. If had to do it over I would just get either a left hand threading tool and run it upside down or run a right hand internal threading tool from the back side of the tenon.
    Nice looking threads Johan!

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