Wheel Specification Codes
Grain Types		A variety of abrasive grains are used to produce industrial grinding wheels. Most commonly used are various forms of aluminum oxide and silicon carbide. There are several types of aluminum oxide used by Jowitt & Rodgers: A - Refined aluminum oxide. A more friable grade of aluminum oxide due to its increased purity and refining process. It is typically used on steel in, their soft state cast iron and soft alloys. B - A very strong and friable modified aluminum oxide grain. C - Green silicon carbide, a more friable silicon carbide grain, primarily for hard, brittle materials. F - Friable white aluminum oxide. An even more friable grain, it is used for very hard and difficult to cut materials. G - Regular aluminum Oxide. This is a tough strong grain It is used on relatively soft and easily machined materials such as low carbon steel. L - Aluminum oxide ceramic hybrid made from re-sintered grains. M - Chrome oxide grains. N - Zirconia grains. Q - Ceramic hybrid form of aluminum oxide. with a crystal structure that remains sharp and durable, continually fracturing along it fine crystal facets, always exposing a sharp edge. T - Zirconia grains. U - Aluminum oxide ceramic hybrid made from re-sintered grains. W - White aluminum oxide. A highly refined and pure grade of aluminum oxide. Most useful for materials that have been heat treated, stainless steels and alloys that resist penetration. X - Silicon carbide is used for low tensile strength materials, such as aluminum, cast iron and other, nonferrous materials. It produces a good visual finish on a variety of metallic and nonmetallic materials. Z - Chrome oxide grains. Abrasive grains are commonly used in combination of mixtures. Typical combinations are GW, AW, AX, GX, QW, QB. Usually a stronger grain is mixed with a more friable grain.
Grain Size		These grains are used in a range of grit sizes which are given a numerical designation. The smaller the number, the larger the grit size. Coarse: 16, 20, 24 Medium: 30, 36, 46, 54 Fine: 60, 70, 80, 100, 120, 150, 180 Coarser grits are typically used to remove large amounts of stock and on relatively soft materials. Finer grits are used to produce smooth finishes with little stock removal and on harder materials. These materials may be used singularly or in combination with each other, depending on a wide variety of factors.
Grades		Grade is a term used to designate the relative amount of bond in the formulation. Grading uses a letter designation, A for the softest to Z for the hardest. Soft: AA, A, B, C, D Medium: E, F, G, H, I Hard: J, K, L, M, N, O, P, Q The grading designations have a relative meaning within an individual abrasive manufacturer's products, but may not relate exactly from one company to another. The grade determines how strongly the grain is held in place. Typically, to grind softer materials, small broken areas, and for rough grinding a relatively "hard" (strong) grade is used. A "softer" grade is used to grind harder materials, or parts with large areas. The words "Hard" and "Soft" wheels have no meaning unless applied to material and area.
Structure		Structure refers to how open the grinding wheel. Assume and "8" for a structure when no other value is indicated in a Jowitt & Rodgers specification. A more open structure in resin bonded wheel can also be created by adding filler materials to create voids in the wheel. Typical structure symbols include: 12, 1A, 2A, 2S, 1F, L20 ..... etc.
Bond		The bond symbol shows the type of bond. Jowitt & Rodgers uses several resin and epoxy bond types. Typical bond symbols include: B1, B2, B5, BF .... etc.
Simplified Marking		Jowitt & Rodgers uses a simplified marking system to denote our formulations on most of our products. An example is shown below: G 24 H B2 The G describes the type of grain, regular aluminum oxide in this case. The 24 describes the grit size, a coarse grit in this example. The H designates the grade, a medium hardness here. The B2 designates the type of bond, a resin bond in this case.