Other naming systemsABSOLUTE DIAMETER DELTA
fractional-inch drill · nominal diameter
53/64
drill bit size.
A 53/64 bit measures 0.8281 in across (21.034 mm).
The fractional diameter is exact; decimal and metric values are conversions.
Calibrated relative diameter · 1 in reference
53/64 · fractional
0.8281 in
21.034 mm Designation53/64fractional
Inch decimal0.8281nominal
Metric conversion21.034millimetres
Where this size sits from 0 to 1 inch 53/64 · 21.034 mm on a zero to 25.4 millimetre scale. Neighbor marks: 13/16, 27/32.
Measured neighbors
What sits beside 53/64.
“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.
Source record
Drill Bit Size Chart.
Fractional sizes are exact rational multiples of one inch.
Open source record