number drill · nominal diameter
#58
drill bit size.
A #58 bit measures 0.0420 in across (1.067 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
#58 · number
0.0420 in
1.067 mm Designation#58number
Inch decimal0.0420nominal
Metric conversion1.067millimetres
Where this size sits from 0 to 1 inch #58 · 1.067 mm on a zero to 25.4 millimetre scale. Neighbor marks: #57, #59.
Measured neighbors
What sits beside #58.
“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