What size drill bit do I need to get for a 3/8 NPT tap?

 

9/16

 

37/64" would be ideal.

 

Man 64s bits are such a PITA to find though in comparison.

 

1/2" + .07" :gay:

 

http://www.use-enco.com/CGI/INSRIT?P...PARTPG=INLMK32

 

www.google.com

we have some noob-*** ************* on this forum. Phillip, you're slackin, buddy.

 

I used a 9/16. Thanks guys!

 

Can I please get some education on drilling and tapping.

What is the relationship between the sizes when picking the fitting, the tap, and the drill bit?

 

google "drill tap size chart"

drill the hole too big and your threads might not be large enough, too small and the tap might not even fit in the hole!

 

http://www.icrank.com/cgi-bin/pagema...rt_npt.htm&t=2

3/8-18? So the drill bit is a 9/16. How is the tap selected?

 

if you got a 3/8 npt fitting, then you want a 3/8 npt tap. then it's just choosing the appropriate drill bit for the tap.

 

Thats sweet.
Thanks man.

 

Question. I was reading in the MS forum that the IAT sensor also uses a 3/8 NPT.

So thats the oil return, and the IAT that uses a 3/8 inch NPT. What else uses a 3/8 NPT. I ask because then its simpler for me to just get one, and use it for everything that needs to be screwed in.

While we are on the topic of fittings, is 3/8 enough for oil return?

Even better question, how do I know what size fittings the turbo needs? The oil feed is threaded while the return is not, and the water is threaded.

 

You can use it for the IAT, oil return, idle air valve fitting, and you might be able to get away with it for the BOV fitting as well, although 1/2NPT is preferred for that just due to size and airflow requirements.

 

Im sorry, just to clarify, you mean the signal to the blow off valve?

Also, can I use it to put a fitting into the outlet from my compressor, it doesnt come with one and id like to keep the boost controller close to the turbo and the actuator.

 

Yes. I am using a 3/8 NPT to -10AN fitting, and it drains just fine. The actual amount of oil flowing through the turbo is amazingly small.

 

He means where the BOV acually mounts on the pipe.

 

Hmm, I cant picture this in my mind. But ok, ill take your word for it.

 

Yeah, where the BOV mounts. Instead of using a silicone coupler with a 1" fitting or something, I used a 1/2" NPT to 3/4" pipe thread fitting, some high-temp silicone sealant, and a small length of 1" heater hose. Coat the 3/4" threads with the silicone, push the 1" hose onto the threads, install BOV in the other end, run signal line up to the cruise control fitting, and let the silicone dry overnight, and you're done. It could leak like a ****, but I don't care because my car is running a MAP sensor.