Inch values are official. Aviation is designed and worked in inches. Millimetres are converted and are not official; where one is shown, the metric drill is the nearest alternative, not the official drill.
Specification
Where to buy| Item | Value |
|---|---|
| Type | Twist drill |
| Point | — |
| Material | As listed: NAS 965 cobalt, 135° split point |
| Use for | Right angle drills, where a pistol grip motor cannot reach |
| Do not use for | Cobalt in aluminium: see the cobalt sheet |
A dash means the sources do not state it.
Sizes
| Size | For | Inches (official) | mm (converted, not official) | Nearest metric alternative, mm |
|---|---|---|---|---|
| #40 | Final, 3/32 rivet | 0.0980 in | 2.489 | 2.50 |
| #30 | Final, 1/8 rivet | 0.1285 in | 3.264 | 3.25 |
| #21 | Final, 5/32 rivet | 0.1590 in | 4.039 | 4.05 |
| #11 | Final, 3/16 rivet | 0.1910 in | 4.851 | 4.85 |
Exact mm = inches × 25.4. The alternative is the nearest 0.05 mm step: commonly used where inch drills cannot be bought, NOT the official drill. The manual sets the tolerance.
Notes
- Listed shank thread 1/4-28: check it against your drill. The Handbook gives no thread.
Where to buy
AmericaDistributor coming soonOur partner for this region is on its way
EuropeDistributor coming soonOur partner for this region is on its way
OceaniaDistributor coming soonOur partner for this region is on its way
Distributors coming soon.
Sources
- FAA-H-8083-31, AMT Handbook, Airframe, Volume 1 (rev. A) — p. 4-15
- Listing as recorded in our catalog — a distributor's threaded drill bits
Educational reference only. not approved data. Always consult the applicable SRM, AMM, or AC 43.13-1B and your certifying authority.