tapping size for 1/8" NPT

[andy4d]

as the subject says, does anybody know the tapping drill size for a 1/8" NPT tap (im fitting an oil temp sender incase your wondering)?
Cheers Andy

 

[EdDanzer]

11/32" drill

 

[elfgriper]

Andy,
Make sure you don't run the tap all the way through. A Pipe thread has a taper to it so that it naturally tightens up as you drive the male threads into the hole. I'v seen leaks when this was done.
-elf

 

[Tryan]

11/32" for softer material ie. aluminium, or for harder material 23/64", my experience!