VARIETIES OF TRUING TOOLS

There has been a very rapid recent development in variety and efficiency of Diamond truing tools for profile grinders. The earlier tools were simple, single, uncut Diamonds. Soon they gave way to Diamonds ground in the shape of a cone.

The next step was the employment of a variety of chisel shapes, especially suitable for truing screw-thread cutters. A considerable range of such tools has been developed. One variant is to use a cubic block of Diamond, since this sort of unit is very strong. The next step in development was to use multiple Diamonds, and then clusters. In all cases the shape required is first cut out in a metal template. The truing tool

carefully follows this template and imposes its shape and. dimension on the grinding wheel. (In the industry, truing tools are sometimes called ‘dressers’.)

A significant extension took place with the introduction of Diamond-bonded wheels and bonded rollers to true the carbide profile grinders. The method is economical, but only on mass-production lines. Sintered bonded wheels can them­selves be used as profile-grinder truers if then shapes are suitable. Much more versatile is the use of electroplated Diamond. The truing wheel or roller is made of exact shape, and dimensions are adapted to allow for the small thickness of a thin layer of Diamond grit that is added. This grit is then bonded on by electrolytic plating, and the final product is a precisely shaped wheel or roller which quickly and accurately re-trues a worn standard carbide profile grinder.

Indeed, for some (expensive) high-quality components an actual bonded Diamond roller is used now as the profile grinder instead of the (much cheaper) sintered carbide roller. Only in special cases is this economic.

Naturally a considerable amount of research has gone into all I of this, and there is a formidable patent bibliography in connection with profile grinding and the truing of grinders.

It is impossible to over-estimate the importance of Diamond truers. Both strong single Diamonds and grit bonds are equally needed for the purpose. Remove Diamonds from engineering, and profile grinding would collapse, and with this collapse mass production would slow down enormously. The term ‘strategic Diamond’ is certainly no exaggeration!