Chuck, you are right, anything that can be done on a CNC, was first done manually. Like you said, it makes single parts faster.
Thinking back to then, we had a retired WW II Army Sargent that did most of our hardenig, he carried a pocket file in his apron and when a part that he hardened was done and drawn back, he would take that file to it and say it is 60 RC. Take that part to the inspectors, he would maybe be l point off.
I made an adjustable sine plate, had it hardened, re-ground it and went and had an inspector I knew look at it on the optical comparator. I don't know why, I didn't know triginometry, but had the book.
It was .0004 off at 5.000 between centers and my mentor said make another pin. I didn't, still have it wrapped in an oil cloth. Make a hardened 3" machinist vise and many sets of parallels all of which I still have. It was fun and a great learning experience.
Last edited by JDW; 01/19/12 06:04 PM.
