Threading idea help needed

Sep 16, 2004 5 Replies
R

Hi, All: I have a piece of SS tubing approx 11/16 Dia that I need to thread externally. It is critical that the threads be coincentric with the bore and it is physically impossible to put this assembly in a lathe (It's part of something else that does NOT come apart. I have about 4.5" of tube sticking out to work with and need to thread the first one inch (The end that's sticking out into the air). The surface it enters is not perpendicular and quite rough. I can't get my mind beyond using a die to cut the threads but am stumped on how to achieve concentricity.



Any ideas appreciated.



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B

Guide rod down the center of the tube? Give it a shoulder with a diameter just big enough to touch the teeth of a die.

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N

Is is actually necessary that the 11/16 tube be threaded? Could you get away with threading the OD of a sleeve with an 11/16 ID and slipping it over the tube? Weld, Loctite, or pin to fasten it.

If the tube's wall is heavy enough, and the assembly isn't too large to mount on a mill to groove the tube OD(or if it is very large, a boring mill), then these might work:

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The threads match standard bearing locknuts.

Ned Simmons

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W

you could make a pilot that is a tight fit in the bore and threaded on the od to start your die from , not the best but has worked for me in the past

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R

On Wed, 15 Sep 2004 20:22:20 -0700, Ned Simmons wrote (in message ):

Excellent suggestion! My undying thanks.

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J

If you have a CNC mill, you could locate over the tube with a CO-Ax indicator or dial test indicator and indi-col, and then thread mill the threads. I use a Micro-100 single row thread mill for these unusual jobs.

Jon

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