BenchReference / Drill sizes / 1.8 mm 1.8 mm Drill Decimal inches 0.0709″
Millimeters 1.8 mm
System Metric
Nearest equivalents in other systems System Nearest drill Size Difference Fractional inch 5/64″ 0.0781″ / 1.984 mm +0.184 mm (+0.0073″)
Number (wire gauge) #50 0.0700″ / 1.778 mm −0.022 mm (−0.0009″)
Letter A 0.2340″ / 5.944 mm +4.144 mm (+0.1631″)
−0.15 mm +0.15 mm 1.8 mm 1.7 mm −0.1 mm 1.9 mm +0.1 mm #50 −0.022 mm ← 1.6 mm −0.2 mm 2 mm +0.2 mm → 5/64″ +0.184 mm → tick position = true diameter · metric neighbors above, equivalents below · window ±0.15 mm
Positive difference = cuts a slightly larger hole than 1.8 mm. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Clearance drill for Neighboring metric sizes Drill Decimal in mm vs 1.8 mm 1.6 mm 0.0630 1.6 −0.2 mm 1.7 mm 0.0669 1.7 −0.1 mm 1.8 mm 0.0709 1.8 — 1.9 mm 0.0748 1.9 +0.1 mm 2 mm 0.0787 2 +0.2 mm
← 1.7 mm (smaller) 1.9 mm (larger) →
Compare 1.8 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 1.8 mm. See all data sources .