Need to know facts about NPTF thread ...
Thread Starter
Racer
Joined: Sep 2005
Posts: 484
Likes: 0
From: Germany
Need to know facts about NPTF thread ...
I have an oil cooler from Summitracing and want to make my own adapter for the filter. The thread for the hoses is 1/2-14 NPTF (dryseal, outer diameter 21 mm)
I need to know three things:
1. Are both, internal and external screw thread conical?
2. What's the correct bore diameter before tapping the 1/2-14 thread?
3. What's the correct bore diameter before tapping a cylindric 13/16-16 (oil filter) thread?
Best wishes from Germany
Eike
I need to know three things:
1. Are both, internal and external screw thread conical?
2. What's the correct bore diameter before tapping the 1/2-14 thread?
3. What's the correct bore diameter before tapping a cylindric 13/16-16 (oil filter) thread?
Best wishes from Germany
Eike
Last edited by Eike; Jun 26, 2007 at 08:16 AM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Drill chart
http://academic.evergreen.edu/projec...abric/pipe.htm
No listings for 13/16
"Are both, internal and external screw thread conical?"
Not certain what you mean here.
If reducing NPT to NPT, both the inner and outer threads of the reducer are tapered.
http://academic.evergreen.edu/projec...abric/pipe.htm
No listings for 13/16
"Are both, internal and external screw thread conical?"
Not certain what you mean here.
If reducing NPT to NPT, both the inner and outer threads of the reducer are tapered.
Racer
Joined: Jun 2005
Posts: 284
Likes: 2
From: Burton Texas
1. Both male and female NPT (National Pipe Thread) threads are tapered.
2. Use a 45/64" drill prior to tapping a female 1/2"-14 NPT thread.
3. 13/16" is not a standard ASTM thread diameter in either course or fine series. I suggest you re-check the thread measurement, it may be metric. If in fact it is 13/16", it is a special and you may have to fabricate your adaptor by salvaging the male part from a filter adaptor off of an engine , or the female part from a mounting plate out of a filter.
Good luck with your project.
2. Use a 45/64" drill prior to tapping a female 1/2"-14 NPT thread.
3. 13/16" is not a standard ASTM thread diameter in either course or fine series. I suggest you re-check the thread measurement, it may be metric. If in fact it is 13/16", it is a special and you may have to fabricate your adaptor by salvaging the male part from a filter adaptor off of an engine , or the female part from a mounting plate out of a filter.
Good luck with your project.
Burning Brakes
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
13/16-16 is a straight UN thread. The minimum minor diameter (or minimum drill/bore size) for an Internal 13/16-16 is .745" or 18.9mm. A 19.0 mm drill would be fine to use.
As stated above - both male and female (external and internal) NPT threads are Tapered or conical. There is an equivalent Straight "pipe" thread standard called NPSM with the same basic diameters and thread pitches.
The 45/64" drill size for female 1/2" NPT thread is essentially the same as an 18.0 mm drill.
Normally, lines and fittings for an external oil cooler would use AN (37° flare) connections. The correct adapters for the cooler itself would be male NPT x Male AN, probably in a -8 or -10 size, depending on the hose diameter you wanted to use. These AN fittings and adapters are available from Summit, Jegs or many other sources.
As stated above - both male and female (external and internal) NPT threads are Tapered or conical. There is an equivalent Straight "pipe" thread standard called NPSM with the same basic diameters and thread pitches.
The 45/64" drill size for female 1/2" NPT thread is essentially the same as an 18.0 mm drill.
Normally, lines and fittings for an external oil cooler would use AN (37° flare) connections. The correct adapters for the cooler itself would be male NPT x Male AN, probably in a -8 or -10 size, depending on the hose diameter you wanted to use. These AN fittings and adapters are available from Summit, Jegs or many other sources.
Last edited by rons85; Jun 26, 2007 at 09:23 AM.
