A graver is a handheld engraving tool, used to scribe designs on metal. It is a period artifact: a graver is shown in a painting of St. Eligius at his work, by Niclaus Maneul, 1515 [John Cherry, Medieval Crafts: A Book of Days, p.50]. It does not appear to have been used in period heraldry.
The graver has no default orientation, but must be explicitly blazoned; the illustration shows a graver with point to base. For related charges, see awl. See also chisel.
William Graver bears: Azure chaussé, a vol argent and overall a graver, point to base, Or.