number drill · nominal diameter
#63
drill bit size.
A #63 bit measures 0.0370 in across (0.940 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
#63 · number
0.0370 in
0.940 mm Designation#63number
Inch decimal0.0370nominal
Metric conversion0.940millimetres
Where this size sits from 0 to 1 inch #63 · 0.940 mm on a zero to 25.4 millimetre scale. Neighbor marks: #64, #62.
Measured neighbors
What sits beside #63.
“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