BenchReference / Drill sizes / 41/64″ 41/64″ Drill Bit Decimal inches 0.6406″
Millimeters 16.272 mm
System Fractional inch
Nearest equivalents in other systems System Nearest drill Size Difference Metric 16.5 mm 0.6496″ / 16.5 mm +0.228 mm (+0.0090″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −10.481 mm (−0.4126″)
Letter Z 0.4130″ / 10.49 mm −5.782 mm (−0.2276″)
−1.302 mm +1.302 mm 41/64″ 39/64″ −0.794 mm 5/8″ −0.397 mm 21/32″ +0.397 mm 43/64″ +0.794 mm 16.5 mm +0.228 mm ← #1 −10.481 mm ← Z −5.782 mm tick position = true diameter · fractional neighbors above, equivalents below · window ±1.3 mm
Positive difference = cuts a slightly larger hole than 41/64″. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring fractional sizes Drill Decimal in mm vs 41/64″ 39/64″ 0.6094 15.478 −0.794 mm 5/8″ 0.6250 15.875 −0.397 mm 41/64″ 0.6406 16.272 — 21/32″ 0.6563 16.669 +0.397 mm 43/64″ 0.6719 17.066 +0.794 mm
← 5/8″ (smaller) 21/32″ (larger) →
Compare 41/64″ with another size
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 fractional size is 0.6406″. See all data sources .