BenchReference

#80 Drill Bit

Decimal inches 0.0135″
Millimeters 0.343 mm
System Number (wire gauge)

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 1 mm 0.0394″ / 1 mm +0.657 mm (+0.0259″)
Fractional inch 1/64″ 0.0156″ / 0.397 mm +0.054 mm (+0.0021″)
Letter A 0.2340″ / 5.944 mm +5.601 mm (+0.2205″)
−0.15 mm+0.15 mm#80#79+0.025 mm#78+0.064 mm1/64″+0.054 mm1 mm +0.657 mm →A +5.601 mm →tick position = true diameter · number neighbors above, equivalents below · window ±0.15 mm
Positive difference = cuts a slightly larger hole than #80. Sizes beyond the window are listed with arrows — they are not close substitutes.

Neighboring number sizes

Drill Decimal in mm vs #80
#80 0.0135 0.343 —
#79 0.0145 0.368 +0.025 mm
#78 0.0160 0.406 +0.064 mm
Data provenance. ASME B94.11M, Twist Drills (standard drill size series) (ASME). Millimeter and inch values are converted with the exact definition 1 in = 25.4 mm; the canonical dimension for this number size is 0.0135″. See all data sources.