fractional-inch drill · nominal diameter
1/64
drill bit size.
A 1/64 bit measures 0.0156 in across (0.397 mm).
The fractional diameter is exact; decimal and metric values are conversions.
Calibrated relative diameter · 1 in reference
1/64 · fractional
0.0156 in
0.397 mm Designation1/64fractional
Inch decimal0.0156nominal
Metric conversion0.397millimetres
Where this size sits from 0 to 1 inch 1/64 · 0.397 mm on a zero to 25.4 millimetre scale. Neighbor marks: #78, #79.
Measured neighbors
What sits beside 1/64.
“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.
This row is at the exposed edge of its series.
Source record
Drill Bit Size Chart.
Fractional sizes are exact rational multiples of one inch.
Open source record