Drill Size Chart for Number and Letter Gauges
measurement drill bits come in 1/64 inch increments. The fractions used are always in their simplest form, i.e. reduced as far as possible, so 2/64 becomes 1/32 for instance. The drill size chart below gives fractional sizes and their metric conversions up to 1 inch. Fraction of an inch inch mm Fraction of an inch inch mm Fraction of an inch