BenchReference

49/64″ Drill Bit

Decimal inches 0.7656″
Millimeters 19.447 mm
System Fractional inch

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 19.5 mm 0.7677″ / 19.5 mm +0.053 mm (+0.0021″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −13.656 mm (−0.5376″)
Letter Z 0.4130″ / 10.49 mm −8.957 mm (−0.3526″)
−1.556 mm+1.556 mm49/64″47/64″−0.794 mm3/4″−0.397 mm25/32″+0.397 mm51/64″+0.794 mm19.5 mm+0.053 mm← #1 −13.656 mm← Z −8.957 mmtick position = true diameter · fractional neighbors above, equivalents below · window ±1.56 mm
Positive difference = cuts a slightly larger hole than 49/64″. Sizes beyond the window are listed with arrows — they are not close substitutes.

Tap drill for

Thread Major diameter Pitch
7/8″-9 UNC 0.8750″ / 22.225 mm 9 TPI

The standard chart recommendation (≈75% thread engagement). Application-specific factors — material, hole depth, tap type — can justify a different drill.

Neighboring fractional sizes

Drill Decimal in mm vs 49/64″
47/64″ 0.7344 18.653 −0.794 mm
3/4″ 0.7500 19.05 −0.397 mm
49/64″ 0.7656 19.447 —
25/32″ 0.7813 19.844 +0.397 mm
51/64″ 0.7969 20.241 +0.794 mm
Data provenance. ASME B94.11M, Twist Drills (standard drill size series) (ASME). Machinery’s Handbook — tap drill charts (Industrial Press). Millimeter and inch values are converted with the exact definition 1 in = 25.4 mm; the canonical dimension for this fractional size is 0.7656″. See all data sources.