Appleton's dictionary of machines, mechanics, engine-work, and engineering (1861)
Appleton, firm, publishers, New York. (1852, D. Appleton & Co.) · New York : D. Appleton · leaf 654
sess this exactitude of form, and although in the attempt to obtain thisperfection, some files are planed before being cut with teeth, still the cutting and the hardening so farinvalidate this practice, that few even of these planed files can retain their perfect straightness. There-fore, as it may… … The file, if concave or hollow in respect to its length, in the manner coarsely exaggerated in Fig. 1649,might be used for works of corresponding convexity; but it would be impossible to file a flat surfacetherewith, as the concave file would only touch the surface at its edges, but the convex side…
Mechanical engineering
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