BenchReference

#23 Drill Bit

Decimal inches 0.1540″
Millimeters 3.912 mm
System Number (wire gauge)

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 3.9 mm 0.1535″ / 3.9 mm −0.012 mm (−0.0005″)
Fractional inch 5/32″ 0.1563″ / 3.969 mm +0.057 mm (+0.0023″)
Letter A 0.2340″ / 5.944 mm +2.032 mm (+0.0800″)
−0.313 mm+0.313 mm#23#25−0.114 mm#24−0.051 mm#22+0.076 mm#21+0.127 mm3.9 mm−0.012 mm5/32″+0.057 mmA +2.032 mm →tick position = true diameter · number neighbors above, equivalents below · window ±0.31 mm
Positive difference = cuts a slightly larger hole than #23. Sizes beyond the window are listed with arrows — they are not close substitutes.

Clearance drill for

Thread Fit
#6-32 UNC close
#6-40 UNF close

Neighboring number sizes

Drill Decimal in mm vs #23
#25 0.1495 3.797 −0.114 mm
#24 0.1520 3.861 −0.051 mm
#23 0.1540 3.912 —
#22 0.1570 3.988 +0.076 mm
#21 0.1590 4.039 +0.127 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 0.1540″. See all data sources.