tap drill for 1/16 -27

Mar 28, 2005 4 Replies

I need to make a threaded hole with a 1/16-27 thread. I have the tap, but have looked up in the handbooks I have and cannot find the tap drill size for this thread. Anybody know what the proper one is?


According to my chart it would take a size "D". The decimal equivalent size is .2460. I am assuming that tap is a NPT taper pipe tap, which is where a

1/16th / 27 tap is located on my chart.

Hope this helps, James Walsh Jr.

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has it listed

thanks. yes. I forgot to mention itwas npt. i couldnt find it in the machinist handbooks. all they listed for the size is some kind of plug gage dimensions.

There's a table 8 on page 1369 of 22d edition, Tap Drill sizes for Internal Dryseal Pipe Threads. D for straight, C without reamer, A with reamer. Joe

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