Conical riser thread on the 210

Discussion in 'Fettling Forum' started by -/-, Oct 9, 2010.

  1. -/-

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    Has anyone info on this?

    I'm stuck here as it is 30TPI and a tad bigger than 1/8". That does'nt rime with anything i have been able to dig up on the web.

    It's not: American NPT, NPTR, NPSM, British BSPT or MEPT

    My grive is that i'm not able to cut conical threads on my small lathe, so i had a faint hope of buying a tap somewhere.
     
  2. Murph

    Murph United States Subscriber

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    You SURE it's 30 TPI?

    I'm finding a 1/8"-28 BSPP with no sweat over at Small Parts

    www.smallparts.com

    Murph
     
  3. -/-

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    Yes sir!

    Tested with a thread gauge. 28 and 32 are no go but 30 TPI fits 100% on the intire length.
    1286631959-R0010172__Medium_.jpg

    What a bitch to do, took me almost 5 min to get it just right.
    1286631966-R0010173__Medium_.JPG
     
    Last edited by a moderator: Jun 26, 2015
  4. -/-

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    The thread is bigger than 1/8" BSPT as you can see. the start (smallest part) measures 10,6mm and the end of the tap (the biggest part) runs out at 10,23mm.

    1286632950-R0010174__Medium_.JPG 1286632961-R00101721.jpg
     
    Last edited by a moderator: Jun 26, 2015
  5. anlrolfe

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    Oh, please solve this one CT!

    please, [-o<
    please, [-o<
    please, [-o<

    AR
     
  6. -/-

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    Easy on bro, i'm working very hard to solve this!!!

    Worst case is that i need to comission a CNC lathe to mashine a tap and from that i can make a die.
    But that will involve several pints of good Danish bitter and some persuation. I hope!!!
     
  7. anlrolfe

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    CT,

    Wish I could come over w/ a dram or more(preferably more) and help you commission that lathe, but there is this large body of water between us that makes that very difficult.

    My previous offer still stands. PT if I can help with "creative juices" or part of a "research grant".

    AR
     
  8. Badger

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    Why not the "offset tailstock" approach?
     
  9. -/-

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    Me lathe dont do that on a threading run! A cone does'nt deliver the ample amount of friction on a small lathe, so 100% correct threading runs is off!!!