letter drill · nominal diameter
M
drill bit size.
A M bit measures 0.2950 in across (7.493 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
M · letter
0.2950 in
7.493 mm DesignationMletter
Inch decimal0.2950nominal
Metric conversion7.493millimetres
Where this size sits from 0 to 1 inch M · 7.493 mm on a zero to 25.4 millimetre scale. Neighbor marks: 7.5 mm, 19/64.
Measured neighbors
What sits beside M.
“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