BenchReference / Drill sizes / 23/64″ 23/64″ Drill Bit Decimal inches 0.3594″
Millimeters 9.128 mm
System Fractional inch
Nearest equivalents in other systems System Nearest drill Size Difference Metric 9.1 mm 0.3583″ / 9.1 mm −0.028 mm (−0.0011″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −3.337 mm (−0.1314″)
Letter T 0.3580″ / 9.093 mm −0.035 mm (−0.0014″)
−0.73 mm +0.73 mm 23/64″ 11/32″ −0.397 mm 3/8″ +0.397 mm T −0.035 mm 9.1 mm −0.028 mm ← 21/64″ −0.794 mm ← #1 −3.337 mm 25/64″ +0.794 mm → tick position = true diameter · fractional neighbors above, equivalents below · window ±0.73 mm
Positive difference = cuts a slightly larger hole than 23/64″. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Clearance drill for Neighboring fractional sizes Drill Decimal in mm vs 23/64″ 21/64″ 0.3281 8.334 −0.794 mm 11/32″ 0.3438 8.731 −0.397 mm 23/64″ 0.3594 9.128 — 3/8″ 0.3750 9.525 +0.397 mm 25/64″ 0.3906 9.922 +0.794 mm
← 11/32″ (smaller) 3/8″ (larger) →
Compare 23/64″ 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 0.3594″. See all data sources .