The complete callout matters: #10-24 is UNC and uses a different drill, while #10-32 is the fine-thread UNF designation covered here.
Why #10 is not a diameter in inches
Numbered machine-screw sizes use a designation system. The reviewed nominal major diameter for #10 is 0.1900 inch; 32 is threads per inch.
Use the full designation
Do not select by the #10 label alone. Confirm 32 TPI with the print, fastener or pitch gauge before drilling.
Important limitation
This lookup is not a tolerance guarantee. Material, tap geometry and required engagement can justify a nearby size.
This lookup is not a tolerance guarantee. Material, tap geometry and required engagement can justify a nearby size.
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.