Centerless grinders are a type of outer diameter (OD) grinder that hold the piece against the wheel with a smaller wheel, known as a regulating wheel. Material is removed through grinding, similar to centered grinding except for the absence of the spindle. A large number of parts can be manufactured in a short time.

The workpiece is set up between the regulating wheel (or back up wheel) and the grinding wheel, and is supported by the work blade (or work rest). Both wheels are rotated in the same direction. The work rest is located between the wheels. The work is placed upon the work rest, and the latter, together with the regulating wheel is fed forward, forcing the works against the grinding wheel. The axial movement of the work past the grinding wheel is obtained by tilting the regulating wheel at a slight angle from horizontal.

Some of the benefits of centerless grinding include the ability to grind parts with geometries that do not allow them to be OD ground, the ability to remove three, five and other odd numbered lobing on the shaft of a part, and to maintain size beyond what is typically capable of an OD grinder due to the low overall pressures spaced out along the workpiece.