letter drill · nominal diameter
N
drill bit size.
A N bit measures 0.3020 in across (7.671 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
N · letter
0.3020 in
7.671 mm DesignationNletter
Inch decimal0.3020nominal
Metric conversion7.671millimetres
Where this size sits from 0 to 1 inch N · 7.671 mm on a zero to 25.4 millimetre scale. Neighbor marks: 7.7 mm, 7.6 mm.
Measured neighbors
What sits beside N.
“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.
Source record
ASME.
The standard text is paywalled. Number and letter series are cross-checked against public manufacturer charts; exact standard edition/page verification remains a release gate.
Open source record