At 16 TPI, one pitch is 0.0625 inch. Subtracting it from the 0.3750-inch nominal diameter produces the same 0.3125-inch value as the reviewed lookup.
A useful exact cross-check
Because 1/16 inch is exactly 0.0625 inch, the simplified major-minus-pitch calculation lands exactly on 5/16 inch for this designation. That agreement does not make the rule universal.
Control the drilling operation
Drill size on the package is nominal. Runout, point geometry, feed, material and tool wear affect the actual hole. Measure or gauge when thread percentage and torque matter.
Important limitation
Do not apply this value to 3/8-24 UNF; that thread has a different pitch and drill recommendation.
Do not apply this value to 3/8-24 UNF; that thread has a different pitch and drill recommendation.
Technical references
- Cle-Line C01112 Tap and Drill Recommendations — Greenfield Industries / Cle-Line. Accessed 2026-11-09.
- NASA Robotics Alliance Project Design Guide, Appendix C — Hole Size Charts — NASA Robotics Alliance Project. Accessed 2026-11-10.
Standards references identify scope and terminology; protected dimensional tables are not reproduced.