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Margin draft

- a border on the face of an ashlar block, usually the width of a chisel. The general assumption is that the border was left untooled to prevent the arris being chipped when the surface of the stone was tooled (see broached). Margin drafts have in fact a far more important purpose. When working a piece of stone, a true surface must first be obtained from which all other surfaces can be aligned. While this appears a simple process it is more skilfull than seemingly more difficult work, for example, cutting mouldings. Margin drafts are worked along two edges of the main surface of the stone, at right angles to each other, starting at the lowest corner. They have to be straight and level. A third draft is then added, parallel to the first and on the same plane, the final draft connecting the first and third is then added. It is usual to use this surface as the face of the finished work, and so, the area contained within the drafts is then cleaned up or tooled as required. The whole process is sometimes referred to as taking a stone "out of twist" or, "out of winding".