Drill Bits / Q Diameter
Q Drill Bits For:
1/8 NPT Drill Size (Pipe Thread)
What size drill bit for 1/8 NPT tap?
A Q drill bit (.3320" hole size) is the correct drill bit size for a 1/8 inch NPT tap. The 1/8th NPT (pipe tap) is a tapered thread designed for a seal. An alternate size is the R drill bit (.3390"), but this diameter may allow leakage across the seal. This size drill causes less thread percentage percentage at the smaller diameter of the thread. The 1/8-27 NPT thread is the most popular thread size used in liquid and gas plumbing applications. It is used in homes, commercial buildings, and industrial businesses for water plumbing and compressed air systems.
Here is a summary of the features of the Q drill bit size:
- Q (0.3320" or 8.43mm) cutting diameter.
- Made in the USA from solid carbide, cobalt, and HSS
- Drill Points: 118, 135, and 140 degree included angles.
- Cutting Edges: 2 flute.
- Drill Lengths: stub and jobber.
- Coatings: Bright, AlTiN (aluminum titanium nitride), TiN (titanium nitride), Black Oxide, Black & Gold Oxide, and Gold Oxide.
Please note the quantities on hand. We have live inventory, so your orders can ship today before 4:30 EST.
