This calculator is useful when making, for instance, a special hex bit. The implementation assumes that either the diameter of the round stock is known or the desired face to face distance across the regular polygon is known. Enter whichever information you have available. (If you have both dimensions you are done!!) In either instance it will also provide the missing dimension. Input the number of sides of the regular polygonal cross section needed, if different than the default hexagon. All regular polygons can be calculated, including triangle, square and n-gon: sides 3 - (or thereabouts). Depth of cut is computed to the nearest ten-thousandth of an inch.
This calculator uses the simple relationship between the diameter and the face-to-face dimension: where number of polygon sides. This relationship is a result of the triangle formed by a line from the center of the circle to the corner of the polygon, a line from this corner to half-way along the side of the polygon, and the line from this half-way point back to the center of the circle. (This is really the radius and half of F2F, but we can eliminate the factor of two from both sides of the equation.)