BenchReference / Drill sizes / 45/64″ 45/64″ Drill Bit Decimal inches 0.7031″
Millimeters 17.859 mm
System Fractional inch
Nearest equivalents in other systems System Nearest drill Size Difference Metric 18 mm 0.7087″ / 18 mm +0.141 mm (+0.0055″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −12.068 mm (−0.4751″)
Letter Z 0.4130″ / 10.49 mm −7.369 mm (−0.2901″)
−1.429 mm +1.429 mm 45/64″ 43/64″ −0.794 mm 11/16″ −0.397 mm 23/32″ +0.397 mm 47/64″ +0.794 mm 18 mm +0.141 mm ← #1 −12.068 mm ← Z −7.369 mm tick position = true diameter · fractional neighbors above, equivalents below · window ±1.43 mm
Positive difference = cuts a slightly larger hole than 45/64″. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring fractional sizes Drill Decimal in mm vs 45/64″ 43/64″ 0.6719 17.066 −0.794 mm 11/16″ 0.6875 17.462 −0.397 mm 45/64″ 0.7031 17.859 — 23/32″ 0.7188 18.256 +0.397 mm 47/64″ 0.7344 18.653 +0.794 mm
← 11/16″ (smaller) 23/32″ (larger) →
Compare 45/64″ 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 0.7031″. See all data sources .