BenchReference

#30 Drill Bit

Decimal inches 0.1285″
Millimeters 3.264 mm
System Number (wire gauge)

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 3.3 mm 0.1299″ / 3.3 mm +0.036 mm (+0.0014″)
Fractional inch 1/8″ 0.1250″ / 3.175 mm −0.089 mm (−0.0035″)
Letter A 0.2340″ / 5.944 mm +2.68 mm (+0.1055″)
−0.261 mm+0.261 mm#30#31−0.216 mm#29+0.191 mm1/8″−0.089 mm3.3 mm+0.036 mm← #32 −0.317 mm#28 +0.305 mm →A +2.68 mm →tick position = true diameter · number neighbors above, equivalents below · window ±0.26 mm
Positive difference = cuts a slightly larger hole than #30. Sizes beyond the window are listed with arrows — they are not close substitutes.

Clearance drill for

Thread Fit
#3-48 UNC loose
#4-40 UNC normal
#3-56 UNF loose
#4-48 UNF normal

Neighboring number sizes

Drill Decimal in mm vs #30
#32 0.1160 2.946 −0.317 mm
#31 0.1200 3.048 −0.216 mm
#30 0.1285 3.264 —
#29 0.1360 3.454 +0.191 mm
#28 0.1405 3.569 +0.305 mm
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 number size is 0.1285″. See all data sources.