Miller that brings back memories, our inspection department was in a climate controlled room, the inspectors wore cotton gloves (for those not familiar with this it was so that their bare hands did not raise the temperature of the piece and increase the size). We called the gages Jo blocks and when handling them they also wore cotton gloves. It was amazing how precise they were ground, by rubbing them together they would stick as there was no gap between the two for air.
We also had a retired WW II gentleman that was in charge of our heat treating department. He used a file and could get within 1 degree Rockwell of hardness when later put on the diamond tester.
