. American engineer and railroad journal . ness,while one of poor steel, but well cut, may cut as fast when new,but fail after a few thousand strokes. To ascertain its qualityaccurately it must be completely worn out in the test. A filetesting and indicating machine was invented in England in 1905and sample files from the leading English and American makerswere tested. Some of these were worn out alter filing away lessthan a cubic inch of iron, cutting at a rate of a cubic inch per10,000 strokes; the best file removed 121 cubic inches of metal,cutting at a rate of 5 cubic inches per 10,000 str
. American engineer and railroad journal . ness,while one of poor steel, but well cut, may cut as fast when new,but fail after a few thousand strokes. To ascertain its qualityaccurately it must be completely worn out in the test. A filetesting and indicating machine was invented in England in 1905and sample files from the leading English and American makerswere tested. Some of these were worn out alter filing away lessthan a cubic inch of iron, cutting at a rate of a cubic inch per10,000 strokes; the best file removed 121 cubic inches of metal,cutting at a rate of 5 cubic inches per 10,000 strokes. The publication of the results of these tests created a sensa-tion. A public file testing department was established in Eng-land and a number of the file makers installed testing machinesand experimented with their product to determine the mostefficient form of file tooth and the most suitable quality of steelto be used. Files are now made which cut at the rate of 8 cubicinches per 10,000 strokes, and as much as 55 cubic inches have. HERBERT FILE TESTING MACHINE. been removed by one side of a single file. The testing machinemakes it possible to trace the effect of slight modifications inthe manufacturing processes. It also permits the user to orderfiles on a basis of quality and check the files supplied. The machine, shown in the illustration, automatically tests filesof any size from 4 to 16 inches, drawing a diagram which in-dicates exactly the work done (cubic inches filed away), thesharpness as indicated by the rate of cutting and the durabilityas indicated by the number of strokes taken before the file ceasesto cut. The file is reciprocated against the end of a test bar,which is supported on rollers and is forced lengthwise againstthe file by means of a weight and chain, giving a constant pres-sure. The bar is withdrawn during the back stroke. A diagramis made on a sheet of section paper wrapped around a drum,after the manner of a steam engine indicator. The drum isg
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
