kb0thn
Stainless
- Joined
- May 15, 2008
- Location
- Winona, MN, USA
After lots of searching over the past two years, I never found good NPT threading examples. But tapping and manually threading external threads got old, so I bit the bullet and figured it out.
Below are proven programs for 1/2" external NPT thread, 3/4" external NPT thread, and 3/4" internal NPT thread. 304 stainless. Tested with ring gauges for external threads and plug gauge for internal thread.
Both internal and external I use NPT form threading tools. That eliminates the need for a perfect internal / external profile to get the truncated crests that NPT uses.
Hopefully this will save somebody else some aggravation
3/4-14 NPT internal:
1/2-14 NPT external:
Below are proven programs for 1/2" external NPT thread, 3/4" external NPT thread, and 3/4" internal NPT thread. 304 stainless. Tested with ring gauges for external threads and plug gauge for internal thread.
Both internal and external I use NPT form threading tools. That eliminates the need for a perfect internal / external profile to get the truncated crests that NPT uses.
Hopefully this will save somebody else some aggravation
3/4-14 NPT internal:
1/2-14 NPT external:
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