Grinding and cutoff wheels are used in industrial applications to remove, shape, and finish materials. Available in various sizes, larger wheels can remove more material quickly. They help smooth rough surfaces, enhancing safety for both users and equipment.
Grinding and Cutoff Wheels Technical Information: Types and Selection
Toolroom Grinding Wheel Types (Used for Surface, Cylindrical, and Tool & Cutter Grinders)
White
For light grinding applications. Made with friable white aluminum oxide, ideal for grinding heat-sensitive steels and light to medium grinding of high-speed steels.
Pink
For light to medium grinding. Made from fused aluminum oxide with chromium and titanium oxide for excellent shape retention. Ideal for alloyed and heat-sensitive steels.
Ruby
For medium to heavy grinding. Made from high-purity calcined alumina fused with chromium oxide, offering excellent form retention and versatility for a wide range of tool steels.
Blue/Gray
For medium to heavy grinding. Made with sharp, monocrystalline, friable aluminum oxide for aggressive cutting, excellent edge retention, and consistent shape. Typically off-white to blue/gray in color.
Ceramic
For light to heavy grinding. Made from a ceramic alumina blend, this wheel offers top-tier performance with the highest productivity, fastest stock removal, and longest lifespan—ideal for grinding a wide range of tool steels.
Grade Selection Assistance
Use coarser grits when:
Finish quality is not critical
Rapid stock removal is required
Grinding involves a large contact area
Use finer grits when:
A smooth surface finish is important
Form accuracy must be maintained
Grinding involves a small contact area
Grit Size | Particle Size | Finish RMS | Finish |
|---|---|---|---|
46 | .020 | Over 32 | Industrial |
60 | .016 | 15-20 | Smooth |
80 | .0105 | 12-18 | Fine |
100 | .0085 | 10-15 | Finer |
120 | .0056 | 8-12 | Very Fine |
150 | .0048 | 6-10 | Mirror Finish |
220 | .0026 | 5-6 | Mirror Finish |
Choosing the Hardness of a Wheel
Hardness:
A wheel's hardness is primarily determined by the bond's holding power—the material that secures the abrasive grains. The bond's quantity is the key factor influencing wheel hardness.
Very Soft | Soft | Medium | Hard | Very Hard |
|---|---|---|---|---|
D, E, F, G | H, I, J, K | L, M, N, O | P, Q, R, S | T, U, V, W, X, Y, Z |
Note: The information in this chart follows industry standards.
The following guide helps determine the appropriate hardness grade, though factors such as stock type, RPM, and desired finish also influence the selection.
Softer Grades | Medium Grades | Harder Grades |
|---|---|---|
Hard metals, such as hard tool steels, carbide | Hard and soft metals | Soft metals |
Rapid stock removal is most important | Balance between rapid stock removal and longer life | Longer wheel life is most important |
Large surface contact | Medium surface contact | Small, narrow surface contact |
Tips For Using Grinding and Cutoff Wheels
1
If the wheel wears too quickly:
Use a harder grade
2
If cutting action is too heavy or slow:
Switch to a softer grade for freer cutting
3
If overheating during cutting
Use a harder or more porous grade for cooler cutting
4
In wet grinding conditions:
Allow for the use of harder grades without burning the workpiece
Bench & Pedestal Grinding Wheel Types (Wheels Used for Off-hand Grinding)
- Gray: Made with semi-friable aluminum oxide; ideal for steel applications.
- Green: Made with friable silicon carbide; used for non-ferrous materials and carbide sharpening.
Safety Tip: Always use grinding wheels in accordance with the manufacturer’s safety guidelines.
Grade Selection Assistance
Grit Selection for Aluminum Oxide
36 Grit | Coarse grinding |
46 Grit | Coarse to Medium grinding |
60 Grit | Medium grinding |
80 Grit | Medium grinding |
120 Grit | Fine grinding |
Grit Selection for Silicon Carbide
60 Grit | General Purpose/Rough grinding |
80 Grit | General-purpose grinding |
120 Grit | Fine Finish grinding |