Saturday, 23 February 2013

Process of Engraving in Jewelry Making



1 Engraver's vise adjustable hand-held vise which holds varying sizes of metal to be engraved:  2 four assorted gravers:  3 flat-sided handles;  4 Arkansas sharpening stone, which should be used with oil?
Engraving is the art of removing surface metal to create a decoration. Much of the finely worked silver and gold that is seen is the work of highly skilled professional engravers, who use techniques and practices acquired over many years. However, most jewelry makers can learn the rudiments of engraving, and it can be used to good effect in a variety of ways.

The tools The cutting edges most often used in engraving are:
• Lozenge - for lines
• Square or diamond - for lines
• Dotter or round
• Square scorper - for removing metal
• Spitstick - for cleaning up edges
• Chisel
• Liner-for making background channels

The steel engraving tool is made or bought separately from the handle, and can be made to the appropriate shape and length to suit individual needs. For example, straight gravers are suitable for working on flat or convex surfaces, while angled or curved ones are better for working on concave or repoussed surface. See Stamping and Blanking for making steel tools.

The handles are made from wood and can be either round or have one flat side, which makes it possible to hold the tool almost level with the work.

Hold the tool in the safe jaws of the vise and use a mallet to hammer down the handle onto it. Always keep the cutting edge crisp and sharp. The belly of the tool - that is, the area where it meets the cutting edge - can be rubbed back to a slight angle with a stone to prevent drag lines being made on the metal. If necessary, the tool can be shortened by holding it in a vise and snapping off the shaft.

Holding the work
Work that is to be engraved must be held steady and flat, but you also need to be able to turn it freely as you work. There are several options. Work can be held in a wooden vise that is itself held on a revolving sandbag, or it can be held in the pitch bowl, which you can turn by hand. If you are working on a small, flat piece, an engraver's hand-held vise is useful. The piece is held by pins that can be located in any of the holes covering the surface of the vise.

Other pieces can be placed on the pin on the bench and held by hand. Hold the work between your thumb and index finger so that you can make a smooth movement when the work has to be turned. Take care to keep your fingers out of the line of the engraving tool. If it slips, you may cut your fingers badly. Holding work by hand can be quite tiring, so if you are working on a complex piece that will take some time to complete, try to find another way.

Holding the tool
The wooden handle of the tool should sit comfortably in the palm of your hand. Your index finger should extend so that it lies along the top of the tool, and the thumb of the hand holding the tool should rest on the surface of the metal being engraved or on the medium in which it is being held. This thumb acts as a guide and a brake and sometimes as a pivot.

Remove the edges up to the First Line
Cutting
Select a tool that is the correct shape for the cut to be made. It must be sharpened on a stone to an angle of 45°. If it is less than 45°, the tip will be too long and may snap. If it is more than 45°, it is more difficult to work and tends to dig into the metal.

To start a cut on a straight line, hold the tool almost vertically so that it gets some purchase in the metal, then quickly lower it so that your thumb can be placed horizontally on the work. Push the tool along the line to raise a tiny curl of metal, then flick up the tool to remove the sliver. Continue in this way along the line.

Curved lines are made with a tool that has been stoned away on one side edge. Turn the work smoothly as the line is being cut the hand that is holding the tool should remain in more or less the same position while the work beneath it is turned.

When engraving is used to remove areas of metal, the area should be outlined with a lozenge chisel and then a second line, approximately 1/22 inch inside the first, should be cut. The area within the second line is then removed with a square scorper or chisel. The base can then be engraved with a lined tool and the edges cut away with a smaller square scorper before being cleaned up with a Spitstick.

Clean up all the edges with a spitstick
Sharpening the graver
Use a fine carborundum stone or an Arkansas stone to sharpen your engraving tools. Put a small amount of oil on the stone and hold the tool flat on its face at an angle of 45° from the stone. Rub the tool along the stone, to and fro, making sure that the whole face remains in contact with the top of the stone. Turn the tool over and rub the stone square along the belly or hold it at an angle if you want to smooth away part of the belly. If the side needs to be shaped or sharpened, hold it at the correct angle and rub in a circular motion.

Writer – Jinks McGrath


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