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  1. #1
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    Default Tapered BSP threads.

    Dumb question time. Does anyone know of a trick for turning tapered BSP threads without a taper attachment?

  2. #2
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Set the compound to the taper and synchronize your brain to the lathe......

    I think you can buy dies that make a tapered thread?

    Even better get a "real" lathe with a TTA!
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  3. #3
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    press the run program button on the cnc lathe

    What material plastic or metal

    cheers
    Harty

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    Quote Originally Posted by harty69 View Post
    press the run program button on the cnc lathe

    What material plastic or metal

    cheers
    Harty
    The current job is brass. 1/8 BSPT and 1/4 BSPT

    I'm wondering how far off I'll be if I turn the major diameter with the compound, and then cut parallel threads on the tapered blank, cut the depth for the full length, and then step back on length on subsequent passes. Lots of teflon tape and thread seal

  5. #5
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    Are you cutting male or female threads? I've got taps if you need them and I think I have dies also, will need to check?
    Kryn

  6. #6
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    Ray

    you could single point thread mill it on your little router

    cheers
    Harty

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    Quote Originally Posted by KBs PensNmore View Post
    Are you cutting male or female threads? I've got taps if you need them and I think I have dies also, will need to check?
    Kryn
    These are male threads, I should just buy the taps and dies.

    Quote Originally Posted by Harty
    you could single point thread mill it on your little router
    I could if it wasn't in bits getting an upgrade from steppers to servos.

    Ray

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    I've got both 1/4 an 1/8 BSP taps, Ray, but won't be home until June 27....
    Cheers, Joe
    retired - less energy, more time to contemplate projects and more shed time....

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    I think even using a die you need to turn the taper.
    Best Regards:
    Baron J.

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    Hmm tough one without a TTA Ray and the dies will only cut parallel.
    The dies I have only start at 1" and gradually move out as you cut.
    Turning a taper won't work if you want to keep in spec and Warragul dies cut straight anyway. The taper doesn't have to be on both.
    A conundrum

    Phil

  11. #11
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    Quote Originally Posted by RayG View Post
    Does anyone know of a trick for turning tapered BSP threads without a taper attachment?
    Find someone with a lathe and TTA?

    Depends a bit on how many and what they are being used for but one of the things we do at work is make up special fittings and weld them to pipes. If you were only talking low pressure and harmless liquids/ gases, I'd suggest thinking about buying some commercially made fittings, doing a cut and shut and silver soldering to the rest of the application.

    Michael

  12. #12
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    Ray,

    What about chasing the threads like they did in the old days. If you screw cut the threads into a a piece of steel plate with the single point threading tool in the lathe chuck and the plate in your tool post, once hardened you have a chaser unless you already have a Coventry set up with the appropriate chasers. It's surprisingly easy to do and self guiding once started, especially in brass. Case hardening the chaser works too if you have no high carbon stuff available.

    Peter.

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    When I cut BSPT threads on a solid bar I use a single pipe die segment (https://www.ridgid.com/us/en/pipe-and-bolt-die-heads) mounted in the tool post.
    The required taper is built into the cutter so it sort of works like a form tool, you just thread like you normally would and withdraw when at the required length. The only thing I changed was to plunge the cutter straight in rather than setting the top slide over, no particular reason for thus it's just how I did it.
    If you need a lend of one give us a yell and I can send one up.
    Cheers,
    Greg.

  14. #14
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    Ray,

    If you can start with a fair length of material you can use a boring head in the tailstock to cut a tapered thread, see:

    http://www.woodworkforums.com/showth...ghlight=franco

    see photos in posts 9 and 19.

    Frank

  15. #15
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    Ray,

    I have a set of stocks & dies. Don't know if it will go down to 1/8th bsp. Mighty big head though. About 8" diam by 6" depth and 10-12 kg at least. I also have bsp taps. Also a TTA.

    Ken

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