RST Engineering wrote:
All of my first year students can hold 20 mil traces and spaces, the C
students can hold 15 mil, and the really good ones can hold 10.

Yeah, but I'll bet your first year students' eyesight is 30 years
younger than that of the average participant in this NGgrin!

--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com
(I was a first-year student 29 years ago)