# diameter of rod prior to threading?



## laddy (Oct 24, 2009)

Hey,
 Is there a chart that lists the diameters of a rod prior to threading? Like reduce 1/4" rod to 4-40 thread....what do you reduce the rod to prior to putting the 4-40 die to it? Thanks in advance to all that help. Fred


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## vlmarshall (Oct 24, 2009)

Here's a threading chart, it lists the Major Diameter of external threads.
http://engineershandbook.com/Tables/threadlimits.htm


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## laddy (Oct 24, 2009)

Hey,
 Many thanks!!!!  Fred :bow:


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## vlmarshall (Oct 24, 2009)

Anytime. ;D


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## shred (Oct 24, 2009)

I use this little chart based on one of Marv's formulas. Works pretty well for our sorts of work. "Ext Thread Dia" is what you want to turn the parent stock to before threading.

http://www.homemodelenginemachinist.com/index.php?action=dlattach;topic=3554.0;attach=1602


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