What we consider to be the "standard" engraving cutter is sometimes referred to as being half-round. Through a process called "splitting" or "halving", a portion of the tool is removed and what is left is a half-round section. (Figure 1)

A quarter-round tool is half split, then the tool is rotated 90 degrees and half of the remaining section is removed leaving a quartered section remaining - thus the term "quarter-round". (Figure 2)

The standard half-round tool is the least expensive of the two and can be sharpened to provide a good balance of clearance and strength so it is the logical choice for the majority of engraving applications.

The biggest advantage to a quarter-round tool is that it provides an exceptional amount of clearance behind the cutting edge. This can be particularly beneficial when engraving soft or "gummy" materials that are difficult to engrave with a standard cutter. A quarter-round tool can also be very effective when making deep cuts, since the added clearance allows the chips to be ejected from the cut reducing the possibility of clogging and melting around the cutter which results in poor cuts. A good example of a deep-cutting quarter-round tool application would be the profiling tool used for ADA cut-out letters which need to be cut from 1/32" or thicker material.

Another application for a quarter-round tool can actually be hard materials such as stainless steel. Since clearance is also an important consideration when cutting these materials, the quarter-round tool can be a good choice.

The down side of the quarter-round is that it is considerably more fragile that its half-round counterpart. This is generally not an issue with soft materials, but it becomes very significant when engraving hard ones. As a result, we specifically do not recommend using quarter-round tools in hard materials with tip sizes less than .030". (Remember, with a quarter-round tool the tip width only measures half the cutting width so a .030" tool will only have a tip that measures .015").

The other disadvantage when using a quarter-round tool in hard materials is that they tend to fracture when they become dull which can result in losing half or even more of the entire flute.