Machine With "Eyes" The above machine has a built-in measuring system which produces accurate spacing within 5/100,000 of an inch or approximately one-fortieth the diameter of an average human hair. General Electric Company's Small Aircraft Engine Department, Lynn, Mass., uses this Linder jig boring machine to manufacture high quality precision control parts for its small gas turbine engines, the T58 and J58, being developed for the U. S. Navy and Air Force, respectively. After determining the desired length between points where holes are to be drilled, the machine's optical measuring system takes over and assures accurate spacing, reflecting the measurements on a screen by means of a photo-electric indicator.