Author Topic: A very complete thread calculator for tubes and such  (Read 953 times)

lloyd-ss

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A very complete thread calculator for tubes and such
« on: February 15, 2017, 04:31:36 AM »
I am just finding my way around the forum and see that there is a lot of neat info to explore here.  I want to throw my 2 cents in about threads.  I make a lot of air tubes and do a lot of single point internal threading, and finding "good" info about threads has been challenging.  If I happen to have a tap of the correct size, I will usually single point the thread to within a few thou and then use the tap to barely clean up the last little bit and bring it into final size.  But what is the maximum major diameter of the internal thread?  I need that not only for information, but to do proper strength calculations.

I finally found a site that has a thread calculator that I really like.  You have to read the glossary to really understand it, but gives the info for internal and external and all the classes.  For example, the maximum major diameter of a 1.125-20 class 2B internal thread is actually   1.1382", not 1.125.  That's important information if the tube wall isn't very thick and the single point threading bar has a sharp point. 

Anyway, here is the link.
http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx


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Christopher

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Re: A very complete thread calculator for tubes and such
« Reply #1 on: February 15, 2017, 06:42:33 AM »
Great find Lloyd, thanks for posting.

Chris
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rsterne

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Re: A very complete thread calculator for tubes and such
« Reply #2 on: February 15, 2017, 09:29:11 AM »
Great find, Lloyd.... particularly the part about the maximum diameter of internal threads with a sharp single point thread tool being larger than the nominal OD....

Bob
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Tinkerer

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Re: A very complete thread calculator for tubes and such
« Reply #3 on: February 16, 2017, 06:48:07 PM »
Great info thanks!!
Glen

oldpro

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Re: A very complete thread calculator for tubes and such
« Reply #4 on: February 17, 2017, 09:52:31 AM »
SWEEEEETTTTT!!!!!
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sixshootertexan

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Re: A very complete thread calculator for tubes and such
« Reply #5 on: February 17, 2017, 12:09:53 PM »
That is a really good free calculator.

May I suggest CNC Machinist Calculator for your smart phone.  I got the paid version and it's well worth the price.

http://cncdirt.com/
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