Diamond Cutter
The most common engraving tool used in the trophy and awards industry is the diamond cutter which is a non-rotating, diamond-tipped tool that is used to scratch lettering into metal - usually brass or aluminum. It consists of a steel shank which has a diamond set in one end that is ground and lapped to a conical point. It is used without a depth nose and, as downward spindle pressure is applied, the point penetrates the surface of the metal and scribes a fine line as the character is formed. Diamond gravers are not available in different tip sizes so we are limited to a rather fine, delicate line of about ten thousandths (.010) in width. A common practice used to enhance the effect of scratch engraving is to trace the letters two or three times. This tends to broaden the stroke and smooth it out. The use of multiple line fonts is also a good way to add dimension to this type of engraving and the lettering can be blackened with oxidizer to give it contrast.

Burnishers
Burnishing is a method of engraving on metals that tends to bridge the gap between scratch engraving and rotary engraving. It is capable of producing wider line widths than a diamond graver without having to rout deeply into the metal. It is a surface marking technique that is generally done on coated metals. It is most commonly used to produce decorative effects on trophy and plaque plates. The tool used for burnishing is called a "burnisher" which is a rotating tool that is used in a motorized spindle. It is usually a carbide or carbide tipped-tool that is ground with four facets that form a cutting edge to the desired tip size. A burnisher is not a cutter. Its function is to remove the surface coating from the material and expose the bare metal.

Rotary Cutters
Rotary engraving is a term that is commonly applied to the type of engraving done on plastics and metals where we cut into the surface of the material. As the name implies, it is done with a rotating cutting tool in a motorized spindle. The rotary cutter is generally a single-flute tool (one with only one cutting edge) that works much like a router bit and produces a cut of specified depth and width. Depending upon how they are made and sharpened, rotary cutters can be used to engrave a wide variety of materials with plastic and metal being the most common. Typically, engraving cutters are single-flute tools, which means they have only one cutting edge. The cutting edge is highlighted in the picture at right. Note the direction of rotation of the cutter. While there is a seemingly infinite number of cutter sizes and shapes, engraving tools fall into two basic categories - conical and parallel.

Types of Rotary Cutters

Conical Cutters
Conical cutters have an angled cutting edge and produce a "vee" shaped, flat-bottomed cut.

Parallel Cutters
Parallel cutters have a straight cutting edge that is parallel to the cutter's axis of rotation and produce a cut with straight walls and a flat bottom. The width of the cut can be as large as the diameter of the shaft (i.e. 11/64" parallel tool can be made to cut up to 4.43 mm wide).

Half Round Cutters
Half-round cutters are made from blanks that have been "split" or "halved" approximately on center through a grinding process. This tool has a cross-section that is half of a cylinder and is the choice for most engraving cutter applications.

Quart Round
Quarter round tools are half-round tools that have a secondary split at 90 degrees to the original flat producing a tool that has a cross-section that is one quarter of a cylinder, they provide more clearance than half-round cutters.

Profiling Cutters
Cutters that have a narrow angle and are used for cutting through material in similar applications to the parallel cutter, but produce a slight bevel on the edge of the material.

Ball Nose Cutters
Have a radius at the tip rather than a flat. They produce a cut with a rounded bottom and are typically used for reverse engraving.

Dovetail Cutters
Produce a cut that has a reverse bevel and are used for making signs that have removable legend strips.

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Rotating Diamonds
Faceted diamond tools that are used in rotating spindles to engrave glass.

Cutting Angle
The cutting angle is the angle formed between the cutter's axis of rotation and its cutting edge. This determines the "V" shape of the groove produced by conical cutters.

Include Angle
The included angle is double the cutting angle.

Clearance Angle
The clearance angle refers to the angle of the cutting edge with respect to the face of the cutter. This angle allows for chip clearance, determines how fine the cutting edge is and is selected based on material properties.

Tip Angle
The tip angle is the angle at the tip of the cutter. Sometimes called the tip-off. Determines the width of the flat at the bottom of the cut.

End Clearance Angle
The end clearance angle is the angle on the back side of the tip that provide clearance for the tip.

Tip Off
The tip-off refers to the flat on the tip of an engraving cutter that determines how wide the cutter will cut. When we refer to tip width or tip size, we are describing the width the cutter produces at the bottom of the cut.

This article is the sole work of Antares Inc. 418-2 Caredean Dr., Horsham, PA 19044, U.S.A.

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