In recent years there has been much controversy over whether to use a carbide burr instead of a steel one. Often the wrong grade of tungsten carbide is used when manufacturing carbide etchers and therefore their quality suffers. If the correct grade of carbide is chosen, there is no reason to have to go back to a steel chisel.
Tungsten carbide has proven over many years to be a reliable and effective material for making cutting tools. The main reasons for its superior performance is that extreme hardness can be achieved and the ability of tungsten carbides to continue to retain its properties, even when red hot. Some knowledge of the material is required to select the correct grade for the required application. Tungsten carbide is a brittle material and care must be taken to avoid damaging the cutting edge by chipping; This is where correct grade selection is most important to deliver a material that will perform well on the job and resist wear and tear from repeated operations. It takes a lot of time to test various grades of tungsten carbide to get the optimum grade for use with carbide etchers.
In general, performance is subject to the hardness/toughness ratio of the material and this can be varied by adjusting the materials used for the production of tungsten carbide powder. Tungsten carbide hard particles can be produced in a variety of grain sizes, the smaller the grain size, the harder the TC alloy. The other main constituent part is the cement that retains the TC particles within the structure and is generally cobalt metal; by adjusting the amount of cobalt in the structure, this can have the effect of increasing toughness as the amount of cobalt increases.
In summary, tungsten carbide can be adjusted in hardness and toughness by varying the amount of cobalt and the grain size of the TC particles. This will give a wide range of hardness settings, from around 800 Vickers hardness to over 2500 Vickers hardness. With this large variation in hardness/toughness available, it can be seen that there is a high chance that an inappropriate grade of carbide will be supplied for use as a carbide burr.
If the right grade is a thing for tungsten carbide, here are the top five benefits of carbide etchers over steel etchers:
1. Carbide burins will last 100 times longer. This means that they are cheaper in the long run.
2. Carbide burrs cut even the toughest materials. You’re not limited in what you can cut, including high-quality watch batons, French watch arbors, etc., that steel engravers can’t touch.
3. Far superior finish transferred to your work. It maintains a much higher level of polish that carries over to your work.
4. Carbide router bits stay sharp longer. Resulting in more working time and less regrinding.
5. Cut faster with less effort. Some people have described cuts as “a knife through butter.”