The Grinding Method.

It makes very little difference upon what class of work a workman may be engaged, whether it be work demanding the greatest accuracy and fine finish (or vice versa), or that the material to be worked be of hard or soft metal, cast or forged,—the grinding machine is the all round finishing machine tool. Just as high speed steel has increased production by displacing carbon steel in many processes, so has the grinding machine increased production by displacing the file, the scraper, the lap and emery cloth for finishing.

It is a mistake to regard the grinding mamachine as essentially a repetition machine. This is entirely erroneous. Whilst the said machine does show to advantage on repetition work (owing to its automatic trip and its all but fool proof accurate feed control) it nevertheless has a much wider scope of usefulness. In the case of the individual article for instance,—after the size is known and a trial cut has been made—the feed control eliminates the problem of human error and reduces the said article to the pre-determined size far more quickly and accurately than any other machine.

The grinding machine has, in the space of a few years, became so universally used that the page 25 Churchill Machine Tool Co., Ltd., manufactures grinding machines of various sizes weighing anything from 20lbs. up to 60 tons. So splendidly are these machines designed and balanced that, weight for weight, there is no other machine that requires as little manual exertion to operate.

Lest there should be any misunderstanding I should like to observe in passing that grinding is a distinct cutting process and is subject to much the same conditions as are those of the lathe or planing machine. A grinding wheel can be too sharp for certain work or too dull; it can be too soft, or too hard. Just as an ordinary tool with only one cutting edge will remove a chip of metal proportional to its strength, so does the grinding wheel with its multiple cutting edges function similarly. The metal removed by a grinding wheel when placed under a microscope bears a striking resemblance to the chips removed by a lathe or similar tool.