Reply With QuoteNPT = National Pipe Thread, ANSI/ASME standard B1.20.1.
Is there a standard that governs the tap used to cut NPT threads? I am particularly interested in 1/4-18 NPT. I am creating a fixture to support a tap. It will need to surround the shaft of the tap and I need to know if a standard governs the size and tolerance of the shaft.
Below is a picture of what I am trying to get a specification on. It is the body of the tapping tool.
Last edited by hogpaw; 05-20-2013 at 12:31 PM.
NPT = National Pipe Thread, ANSI/ASME standard B1.20.1.
I uploaded a picture on the initial post that shows what part of the tapping tool I am trying to find a dimension and tolerance for.
When you asked the manufacturer what did he say? What? You didn't ask the manufacturer? Hmm...
jboggs,
There is more than on manufacturer of NPT taps, hence my initial question: Is there a standard that governs the manufacture of NPT taps?
"Is there a standard that governs the manufacture of NPT taps?"
Who would know the answer to that question better than a manufacturer?
Hogpaw, listen to JB! At a guess I would say there probably is a loose standard that is more of convenience than ideal. I suspect the shank diameter will be dictated largely by the square on the top. The square, which does have a specification for will probably define a convenient diameter shank.
Lemme just say more Bytes and say again, listen to JB.
Per ANSI B94.9-1979
1/4-18 NPT Shank Diameter is .5625 +.000 / -.002 if ground threads. Shank Dia. is .5625 +.000 / -.007 if cut threads.
Square drive on the tap will be .421 +.000 / -.006
Awesome suggestion JBoggs!!! Got the info I needed....from the Mfr.
Thank you rwolfejr
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