Calibrated hands...story time! Out at the flight school, the owner had been working on aircraft for like 40 years and when in a pinch, would make or alter parts by hand...you know, with files and grinders and such. One of the flight instructors had a thing for mindbender puzzles, like the horseshoes chained together, puzzle boxes, stuff like that. This one morning the instructor brought in this steel polygon with a bunch of different but equal surfaces, each surface having a square hole in it. The polygon came with a cube, approximately the same size as all the holes. The puzzle part was the cube would only fit in one of the holes going one direction...enough to drive Rubik crazy. So the instructor explains the puzzle, hands it to the owner who carefully feels both the polygon and cube for about 10 seconds, then drops the cube in a hole and shakes it around. Priceless! While learning machine tool technology the instructors paired us up on machines. One day while turning a project down, our instructor came up and asked "What are you guys doing?" Told him we were measuring to see how much more we needed to take off. He feels it up with his calibrated fingers and says "You have another 0.043" to go." Me and my lab partner looked at each other and the instructor says "Measure it!" Break out the dial caliper...it measured between 0.042"-0.043...our jaws dropped. Amazing! Jon