Cut off Discs

Africa bearings supply high quality cut off discs and grinding wheels at affordable prices.

Characteristics of cut off discs

•  Material
• Grain size
• Wheel grade
• Grain spacing
• Bond type

Abrasive Grain

The abrasive aggregate is selected according to the hardness of the material being cut.

• Aluminum oxide (A)
• Silicon carbide (S)
• Ceramic (C)
• Diamond (D, MD, SD)
• Cubic boron nitride (CBN)

Grinding wheels with diamond or CBN grains are called super abrasives. Grinding wheels with aluminum oxide (corundum), silicon carbide, or ceramic grains are called conventional abrasives.

Grain size

From 10 (coarsest) to 600 (finest), determines the average physical size of the abrasive grains in the wheel.

• A larger grain will cut freely, allowing fast cutting but poor surface finish.
• Ultra-fine grain sizes are for precision finish work.

Wheel grade

From A (soft) to Z (hard), determines how tightly the bond holds the abrasive.

• A to H for softer structure, I to P for moderately hard structure and Q to Z for hard structure.
• Grade affects almost all considerations of grinding, such as wheel speed, coolant flow, maximum and minimum feed rates, and grinding depth.

Grain spacing

Spacing or structure, from 1 (densest) to 17 (least dense).

• Density is the ratio of bond and abrasive to airspace. A less-dense wheel will cut freely and has a large effect on surface finish.
• It is able to take a deeper or wider cut with less coolant, as the chip clearance on the wheel is greater.

Wheel bond

How the wheel:

• Holds the abrasives
• Affects the finish
• Affects the coolant
• Minimum/maximum wheel speed.