charge air drilling

[anonymous_user]

I need to install a charge air sensor on a 1-piece intake. Since I don't have the sensor yet, what size threads are they?

[GLHNSLHT2]

3/8ths pipe tap and a 37/64ths drill.

[anonymous_user]

Thanks

Hmm...

My sources tell me that 3/8-18 NPT takes a 9/16 drill bit. 37/64 is only a weee bit bigger. Shouldn't make a difference, should it? (I don't have a 37/64 bit)

[bobr19]

Quote:

Originally Posted by anonymous_user Thanks Hmm... My sources tell me that 3/8-18 NPT takes a 9/16 drill bit. 37/64 is only a weee bit bigger. Shouldn't make a difference, should it? (I don't have a 37/64 bit)

Should work fine--bobr19

[GLHNSLHT2]

McMaster carr has a one for not too much $$$. Just get it with a reduced 3/8ths shank. With how thing the metal is and getting that pipe tap started I'd rather have the extra .013 thou.

[minimopar]

Go with the smaller bit, especially if you are hand-drilling. The casting is aluminum and the tap is tapered, so it will have no problems taking out the extra material. When hand-drilling a hole to be tapped, I always take 1/64th off the recommended size, since the drill will tend to hog-out about that much even with the steadiest of hands.

[william]

FWIW, I have done a dozen or so with a 9/16" bit and a hand drill and they all worked fine. I have found that I get best results by only running the tap about 1/2 to 3/4 of the way in, or the sensor comes close to the end of its threads. I wouldn't want to use a bit any larger or the sensor would be too loose. Like GLHNSLHT2 mentioned be mindful of chuck size as well, most standard bits that size won't fit in a 3/8" chuck hand drill.

[minimopar]

You can also get larger adapter chucks at the hardware store that will thread on the smaller drill shafts. Good for making a cheapo drill more useful or handling large bits in a cordless.