The Type 12B9H is a circular, single-sided configuration. The surface is flat with cupped edges, measuring 1/8-by-7/8-by-1 1/4 inch in size. This system is typically applied for cylindrical materials that allows the user to move the surface around the piece smoothly, but can also be used for narrow edge work including grinding small burrs off the surface of a previously lathed piece of material.
The Type 14A1 is a two-sided, circular, flat-face configuration, however the edges are notched on the radius, measuring 8 by 3/8 inches by 32mm at the edges. This system is typically applied on wide, flat materials, however the notched characteristic of the grinder's edge allows the user to also work the narrow edges of the material. This configuration is highly useful for working on large pieces.
The Type 14F1R configuration is built as a two-sided radius shape. This tool's hub hole is located on one side of the surface, with the other side funneling down to a near point at the edge that measures 10 by 3/8 inches by 32mm. This tool is typically used on cylindrical material and allows the user to apply a full range of movement along and around the surface of the work.