Engraving Fact Sheet

 Description & Application

The most common form of engraving in the trophy and awards industry is done using a non-rotating diamond-tipped tool to scratch lettering or designs in metal. The process is frequently referred to as "diamond engraving," "scratch engraving," or "diamond drag" with the latter probably being the preferred terminology. Diamond drag engraving can be performed on virtually all metals and in some applications, glass and plastics. In the awards industry, it is typically used as a quick, easy, and inexpensive method of engraving the pre-finished brass and aluminum plates on trophies and plaques. On colored plates, the diamond penetrates the coating and exposes the bare metal; a gold color on the brass and silver on the aluminum. On material that has a clear coating, the engraving can be blackened with an oxidizing solution to add contrast. (See "Color filling Fact Sheet") Return to Top or Continue...

Diamond Gravers
The tool that is used in the diamond drag operation is referred to as a "diamond graver." It consists of a steel shank that has a diamond set in one end. The diamond is ground to a conical point and then "lapped" to create a smooth, polished surface. This is an important step in the manufacturing process as the brilliance of the finished cut is largely determined by the finish on the diamond.

General-purpose diamond gravers have an included angle of 120°, 130°, or 140°. In addition to the standard tools, Antares also offers specialty gravers with included angles of 90° and 100° which can be used for delicate engraving on epoxy coated pens. These tools are considerably more fragile than the standard ones and are not intended for use on metal.

Antares diamond engravers are available for all popular engraving machines. The most common is the "diamond insert" which measures 1/8" × 1-1/8" and has a flat on the shank. It is inserted into the bottom of a non-rotating "diamond spindle" and is held in place by a set screw tightened against the flat.

Top-loading diamond gravers (those that are inserted into the top of the spindle and held in place by a cutter knob) are available in 1/8", 11/64", 1/4", 4 mm, and 6 mm shank sizes. While these tools are used in rotary spindles, the engraving operation is performed without the motor running. Using the diamond graver as a rotating tool can shorten its life and can damage it beyond repair.

A diamond graver is very durable and will last a long time, but like any cutting tool, it becomes dull and less effective after use. As the diamond wears, the point becomes rounded and instead of slicing through the metal cleanly, it has a tendency to tear it and produce rough, uneven cuts. Another problem caused by a worn diamond is that the blunt point can smear the surface coating into the cut. On colored plates, the result is an uneven, blotchy appearance. On plates with a clear coating, the visual effect is minimal, but oxidizing may be a problem. The oxidizer blackens the bare metal, but not the areas where the lacquer has been pushed into the cut

Diamond gravers can be relapped (resharpened) to restore the point to its original condition. Due to the minimal cost difference between relapping and a new tool, we do not recommend relapping 1/8" gravers, however it is cost-effective for the 11/64", 1/4", 4 mm, and 6 mm tools. A dull diamond offers more resistance to the metal and is subject to more pressure. Continued use can fracture the diamond or tear it from its setting.

Dull vs. Sharp

Procedure
The diamond drag operation is a simple one. As downward spindle pressure is applied, the point of the diamond penetrates the surface of the material and then scribes a groove as the spindle moves laterally to form a character. In this type of engraving, there are no width or depth options. To a limited extent, both of these aspects are a function of the amount of pressure applied, the sharpness of the diamond, and the number of passes made. Generally, the width of the stroke winds up being about ten thousandths of an inch (.010"). There are no "special" non-rotating gravers capable of producing strokes of specified widths. If broader strokes are required, burnishing would be a good alternative. (See Burnishing Fact Sheet)

As a diamond graver moves through the material, there is a considerable amount of sideward pressure exerted on the tool. Therefore, the best situation is to use a diamond insert in the stationary diamond spindle as it is rigid and provides support. When a graver is used in a rotary spindle, the sideward pressure pushes against the spindle and can ultimately cause damage to the lower spindle bearings.

The overall appearance of the engraving can vary greatly depending on the metal, the font, and the technique used. On trophy brass, which is a relatively hard material, the line will be crisp and defined. Lacquered aluminum is softer and tends to yield a cut that is rougher and not as uniform. One way to improve the engraving quality on softer materials is to use less pressure.
Very hard metals such as stainless steel and hardened steel will produce a crisp, but fine line. Depending on the hardness, the stroke can be broadened and deepened by engraving the letters two or three times. The use of multiple-line fonts is also a good way to achieve the appearance of a bolder character in all materials.

It is also possible to engrave glass and some plastics using the diamond drag technique. Scales and grids that have extremely fine lines can be produced on glass or acrylic lenses. The basic techniques are the same as for metals, but the pressure becomes a critical factor in maintaining uniform line width and needs to be precisely controlled to assure optimal results. Use of a spring-loaded burnishing adapter can help in maintaining a constant controlled pressure.