This highly useful gage shows at a glance the correct size tap drill for any common size machine screw tap in "NF" National Fine or "NC" National Coarse Thread Series, that will leave the right amount of stock for approximately 65% full thread. The gage also shows the correct body size drill to use. In addition, there are 60 holes marked with the number size and decimal equivalent of the drill that fits each hole. Example: a size 2-56 tap (No. 2 tap with 56 pitch) calls for a No. 50 tap drill and a No. 44 body drill.
The gage has a black matte finish with information steel stamped on one side and white marked on the reverse side for quick, clear reading. The gage is thoroughly tested for accuracy after hardening. Approximate size, 5/64" thick by 2 5/16" wide by 6 1/4" long.