Q: I’m making a series of octagonal salt shakers in sheet silver, and I need to score the lines where the metal folds so the proper angles are produced. It’s not hard to do this on narrow bands of silver, but lines several inches long are another story. Short of purchasing an expensive scoring tool setup for the flex-shaft, is there a simple way to do this?
A: Find an old hand file. Heat the last half inch or so of the tang (not the file part) to a nice red, and bend it over forming a right-angled hook that hangs down maybe a quarter inch or a bit more. Grind the end to an angled point, at the angle you need for your bends. The face of the hook that faces the rest of the file is smoothed flat, and the edges facing out to the sides of the file are cut to that angle, as well as angled back a little away from the file, so the tip of the hook becomes a cutting edge when the file is pulled towards you. Don’t make the relief angle of that hook too steep, or it will tend to dig in too much. Just a couple degrees is enough.
Now reheat the end of the hook to a red heat, and quench to harden it. Lightly sand the surfaces till they’re bright again, and reheat the tang slightly above the point (the bend) watching the colors form. Quench again when the cutting end reaches a dark yellow. Now resharpen those faces, just as you’d do with a graver. This is a scoring tool. It amounts to a “pull” graver, and will score the metal for your folds when repeatedly drawn down the line you need.
To guide the tool in that line, use “C” clamps to clamp a piece of steel, such as a good steel ruler, to your silver, with the edge of the steel slightly set slightly back from the marked line. The amount of setback can be seen by placing the scoring tool’s tip on the desired line, and seeing where to put the rule so the side of the tool rides along it. This works best if the guide piece is fairly rigid, and a bit thicker than normal steel rulers, as well as if the edge does not have cut graduations, so this is best done with another piece of tool steel instead of a ruler. If you like, file the guiding edge to a slight bevel to clear the sides of the cutting point. To use the tool, just clamp your guide bar to the sheet stock as needed, and draw the cutting tool along the guide bar. Repeat until it’s deep enough.
Just as with a graver, the geometry of the belly facets of the cutter will determine how much the tool digs in or not, and also whether it’s prone to wanting to cut to one side instead of straight. So some trial cuts may be needed to fine-tune the tool. Once made, though, it’s surprisingly quick to use, and works better on your longer cuts than on short ones like across a ring shank, since the beginning and endings of each cut tend to dig in a little more. So if you leave your stock slightly larger then needed, score the lines, and then trim to size, you can trim off any uneven bits at the beginning and end of each scored line.
by Peter W. Rowe M.F.A., G.G.