- Indicates correct size tap drill for any National Coarse or Fine tap from 2–56NC to 1/4–28NF to produce 65% full thread
- Gauge also indicates correct body size drill and provides 60 holes marked w/number size and decimal equivalent of drills from No. 1 thru No. 60
- 2-5/16” wide by 6-1/4” long
- Tap size: 2-56 to 1/4-28, tap drill: 50 to 3
- Body drill: 44 to 1/4 and drill number: 1 to 60