Loose Leaves.
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THE older types of Marine engineer and general engineer can rarely be brought to believe that motor engineering genuinely works to the fine limits so freely specified by designers. We listened to one of the type a few days ago uttering his scepticisms of the bulldog order andwondered it he had come from the era when they bored out a cylinder with a cold-chisel. "I see from this • drawing," s.aid. he to his designer, "that you are demanding that the valves shall not vary in stem length by more than a thousandth of an inch between the seating and the end of the stem. Valves can't be made so accurately as that, -sir ! " " Oh! yes they can," said the designer, "and I can tak-eyou to a works and prove that to be so." The critic was induced to go and see the operation for himself, and was shown valves being placed by girls into a coned jig, locked in place; and the end of the stem finished to correct length, after which another girl put them one by one into a seating, the end of the stem bearing on a lever which moved a pointer over a dial, so that a thousandth of an inch showed up as a quarter of an inch.
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Provided the pointer stopped between two red marks, a quarter of an inch apart, the valve was passed. And the Cost of these valves is only_ 7c1, apiece. The critic was dumb for an hour ! Accuracy of workmanship to extremely fine limits is the secret of rapid assembly and cheap maintenance.