The wire gauge number ranging from 107 to 1 and letters ranging from A to Z. Fractional sizes are measured in inches and metric sizes are measured in millimeters. In this drill bit size table, standard size drill bits available in several measurement systems, you can find wire gauge number, letter, fractional and metric drill sizes. A smaller Thread height means a larger tap. A larger Thread height means a smaller tap drill size. ANSI B94.11M-1979 specifies the size standard of straight shank twist drill bits with working length from 1/64 inch to 1 inch in increments of 1/64 inch.ĭrill Size Chart/Table – Drill Bit Dimensions Chart In tapping, it is customary to express the thread height (Sometimes called thread depth) as the relation in percentage between the actual depth and the maximum depth. Fractional-inch drill bit sizes: the drill bit sizes are written as irreducible fractions.They are loosely based on the Stubs Steel Wire Gauge. Gauge Number Drill Bit Size Submit another drill bit gauge size below for us to size for you. Number and letter gauges do not follow a formula or standard increments. 4.0386 mm Drill Bit Size Chart For additional information about what drill bit to use, you may also want to take a look at the Drill Bit Size Chart which includes fractional inch drill bits, gauge wire drill bits, and metric drill bits sorted by size. Number and letter gauge drill bit dimensions are often used for twist drill bits rather than other drill forms, and are still in common use in the U.S.
Smaller sizes will be listed in the drill dimensions chart, but those are rarely encountered in practice. Number and letter gauge drill bit sizes: the number drill bit gauge sizes range from size 80 (the smallest) to size 1 (the largest) followed by letter gauge size A (the smallest) to size Z (the largest).