BenchReference

6.8 mm Drill

Decimal inches 0.2677″
Millimeters 6.8 mm
System Metric

Nearest equivalents in other systems

System Nearest drill Size Difference
Fractional inch 17/64″ 0.2656″ / 6.747 mm −0.053 mm (−0.0021″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −1.009 mm (−0.0397″)
Letter H 0.2660″ / 6.756 mm −0.044 mm (−0.0017″)
−0.544 mm+0.544 mm6.8 mm6.6 mm−0.2 mm6.7 mm−0.1 mm6.9 mm+0.1 mm7 mm+0.2 mm17/64″−0.053 mmH−0.044 mm← #1 −1.009 mmtick position = true diameter · metric neighbors above, equivalents below · window ±0.54 mm
Positive difference = cuts a slightly larger hole than 6.8 mm. Sizes beyond the window are listed with arrows — they are not close substitutes.

Tap drill for

Thread Major diameter Pitch
M8 × 1.25 0.3150″ / 8 mm 1.25 mm

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

Neighboring metric sizes

Drill Decimal in mm vs 6.8 mm
6.6 mm 0.2598 6.6 −0.2 mm
6.7 mm 0.2638 6.7 −0.1 mm
6.8 mm 0.2677 6.8 —
6.9 mm 0.2717 6.9 +0.1 mm
7 mm 0.2756 7 +0.2 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 metric size is 6.8 mm. See all data sources.