Punch-and-die sets have been designed for use in rounding corners of rectangular metal sheets to specified radii. One of the traditional procedures for rounding a corner on a rectangular metal sheet is to first make a rough cut with a band saw and/or hand metal snips, then to file the roughly cut edge; this procedure is time-consuming and does not result in an accurate radius. The use of a punch-and-die set of the present type takes less time and results in a corner with an accurate radius.

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The Punch-and-Die can be used to cut a corner of a rectangular metal sheet to a desired radius. This is a simplified drawing; some details have been omitted for clarity in depicting basic shapes.

The figure shows a punch and die of the present type. Of course, the dimensions of the punch and die must be chosen to suit the thickness of the metal sheet and the corner radius to be formed. Thus far, punch-and-die sets have been made for sheet thicknesses up to 0.125 in. (≈3.2 mm) and corner radii from 0.2 to 2 in. (≈5 to 51 mm).

This work was done by Cecil L. Wachsman of Ames Research Center. ARC-14230