
Feb 24, 2025 ● hireCNC
How many threads per inch on an Imperial micrometer thimble? Don't cheat, figure it out in your head.
Excerpt from our "Morning Machinist" newsletter. Like this content? See full articles and subscribe here; https://www.morningmachinist.com/subscribe

Top responses include:
- “A question on my high school class I taught. Most got it”
- “25 years ago this was actually a question an employer asked me in an interview. He said a machinist should be able to figure this out. Pretty easy when you think about it.”
- “Good question.... that I've asked hundreds of "machinists". Very, very few knew and most of them couldn't figure it out.”
“I ask this very question when interviewing potential employees. It tells you a lot about them:
1. They know how a micrometer works (you'd be surprised).
2. They know about T.P.I. and threads.
3. If they don't already know, but can figure it out, they have math skills.”
“1 divided by .025 = 40.” The machinist trade is based off a screw thread! Some of us are not mechanically inclined, but helps to be mathematically inclined.
Numbers don’t lie!”
- “Well, it moves 25 thou per turn. And there are 1000 thousandths per inch so 1000/25= 40”