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Confused about 1" NPT - hole wizard

Question asked by Eric Snyder on Dec 7, 2016
Latest reply on Feb 26, 2018 by Brian Brazeau

Really confused about 1" NPT threads using hole wizard. Actually all Hole wizard NPT hole sizes do this.

 

Below is an assembly with a 1" standard wall NPT pipe in a standard 1" NPT hole wizard hole. You can see that Solidworks is adding a tapered hole that the pipe thread does not cut into. This seems weird to me??? The recommended drill size for a 1" NPT is 1 5/32 (1.15625"). That is the lower hole diameter. Why is the tapered hole marked in blue there at all??? MY problem happened when I put a 1" NPT in a 1" thick plate and had it machined. Now there is not enough aluminum to cut threads into - remachining $$$.

 

Capture1.PNG

 

The standard NPT threads from the hole wizard start at the blue surface:

Capture2.PNG

 

And not at the first surface:

Capture3.PNG

 

Seems wrong to me...help me understand???

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