If you need to know how many threads per inch a No. 5 machine screw has, then this wheel is for you. There is a lot of information on this wheel. I wish I knew what to tell you about it. I know nothing about woodruff keys or tap drills.
What I can tell you is that this is no ordinary wheel. No, sir! Derck's Gauge Dial has not one, not two, not even three wheels. It has SIX! It has four outer wheels (that include the delightful perforated edges I always like) and two inner wheels. If you'd like to see this wheel in action, head on over to my Instagram page and check it out. You can find me under my name or at @saintpud.