number drill · nominal diameter
#74
drill bit size.
A #74 bit measures 0.0225 in across (0.571 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
#74 · number
0.0225 in
0.571 mm Designation#74number
Inch decimal0.0225nominal
Metric conversion0.571millimetres
Where this size sits from 0 to 1 inch #74 · 0.571 mm on a zero to 25.4 millimetre scale. Neighbor marks: 0.6 mm, #75.
Measured neighbors
What sits beside #74.
“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