letter drill · nominal diameter
L
drill bit size.
A L bit measures 0.2900 in across (7.366 mm).
The inch decimal is the published nominal designation; millimetres are a conversion.
Calibrated relative diameter · 1 in reference
L · letter
0.2900 in
7.366 mm DesignationLletter
Inch decimal0.2900nominal
Metric conversion7.366millimetres
Where this size sits from 0 to 1 inch L · 7.366 mm on a zero to 25.4 millimetre scale. Neighbor marks: 7.4 mm, 7.3 mm.
Measured neighbors
What sits beside L.
“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