BenchReference / Drill sizes / 10.4 mm 10.4 mm Drill Decimal inches 0.4094″
Millimeters 10.4 mm
System Metric
Nearest equivalents in other systems System Nearest drill Size Difference Fractional inch 13/32″ 0.4063″ / 10.319 mm −0.081 mm (−0.0032″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −4.609 mm (−0.1814″)
Letter Z 0.4130″ / 10.49 mm +0.09 mm (+0.0036″)
−0.832 mm +0.832 mm 10.4 mm 10.2 mm −0.2 mm 10.3 mm −0.1 mm 10.5 mm +0.1 mm 10.6 mm +0.2 mm 13/32″ −0.081 mm Z +0.09 mm ← #1 −4.609 mm tick position = true diameter · metric neighbors above, equivalents below · window ±0.83 mm
Positive difference = cuts a slightly larger hole than 10.4 mm. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring metric sizes Drill Decimal in mm vs 10.4 mm 10.2 mm 0.4016 10.2 −0.2 mm 10.3 mm 0.4055 10.3 −0.1 mm 10.4 mm 0.4094 10.4 — 10.5 mm 0.4134 10.5 +0.1 mm 10.6 mm 0.4173 10.6 +0.2 mm
← 10.3 mm (smaller) 10.5 mm (larger) →
Compare 10.4 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 10.4 mm. See all data sources .