Need Drill Bit Size for 1/8" NPT

[CampbellCarl]

Anybody have a chart or know what size drill bit I need to then chase with a 1/8" NPT tap? I appreciate your help! Installing an oil temp sender in the remote oil filter housing.
Thanx!
CC

[CampbellCarl]

Think i found my own answer........does .332" sound right?
CC

[502 JET]

The chart I have says letter drill (R).
I cant measure the drill cause some fokker in the shop lost it.
Just googled letter drills, you were close. (R) .339

[rrrr]

You could Google "1/8 NPT drill size" and get a result...
http://bobmay.astronomy.net/misc/drillchart.htm

[bajarunner]

1/8"-27 npt tap calls for a .3390" ltr "R" drill.
I use a 21/64 drill bit which measures at .3281" this works perfect for me everytime.
The next "common" drill size up is a 11/32" which measures .3438" and is
a little to large.

[Taylorman]

I tapped a 1/8 npt hole last night. Letter R bit. I tapped it a little to deep. Be careful not to make the same mistake.

[CampbellCarl]

Thanx all.......got 'er done!
CC

[jimsplace]

TAYLORMAN
If you haven't already done it - use several wraps of teflon tape to build it up. I have done that too(gone to deep). If it is being used around the oil supply, be sure to trim off the bottom part of the taped fitting so there is no chance of the tape getting into the oil supply and stopping up something. Also, when that fitting needs to come out, be sure and clean the internal threads to make sure there is no little pieces of teflon left in the threads.