BenchReference / Drill sizes / 7.7 mm 7.7 mm Drill Decimal inches 0.3031″
Millimeters 7.7 mm
System Metric
Nearest equivalents in other systems System Nearest drill Size Difference Fractional inch 19/64″ 0.2969″ / 7.541 mm −0.159 mm (−0.0063″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −1.909 mm (−0.0751″)
Letter N 0.3020″ / 7.671 mm −0.029 mm (−0.0011″)
−0.616 mm +0.616 mm 7.7 mm 7.5 mm −0.2 mm 7.6 mm −0.1 mm 7.8 mm +0.1 mm 7.9 mm +0.2 mm 19/64″ −0.159 mm N −0.029 mm ← #1 −1.909 mm tick position = true diameter · metric neighbors above, equivalents below · window ±0.62 mm
Positive difference = cuts a slightly larger hole than 7.7 mm. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring metric sizes Drill Decimal in mm vs 7.7 mm 7.5 mm 0.2953 7.5 −0.2 mm 7.6 mm 0.2992 7.6 −0.1 mm 7.7 mm 0.3031 7.7 — 7.8 mm 0.3071 7.8 +0.1 mm 7.9 mm 0.3110 7.9 +0.2 mm
← 7.6 mm (smaller) 7.8 mm (larger) →
Compare 7.7 mm 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 metric size is 7.7 mm. See all data sources .