In one of my past lives, I worked for a company where they used a competing CAD software (rhymes with Tormentor) there was a nice function that would apply external threads to a cylinder and then in Drawings, it will automatically write the callout for the machinist.  Now that I'm in Solidworks I don't have that feature, so I have to use my so called brain.

My cylinder is 8.5" in diameter and I used Helix and Sweep to make a thread with 8 teeth per inch.

Here is my drawing callout.  Does that look somewhat correct?