Grinding is a process that produces very accurate dimensions and fine finishes. It is used to rapidly remove large volumes of metals and also for taking away small amounts of material at a time. Grinding can be used to achieve tolerances of .001”.

Centerless: In this process, the piece is supported by a workblade that is set between a regulating wheel and a high speed grinding wheel with a larger diameter. Because the workblade is sloped, the piece is above the center of wheels. This allows for accuracy without a center cut.

Lathe Turning: In this process, the diameter of the piece is reduced by turning a bar horizontally while a tool bit cuts into the piece. This results in a smooth finish and allows for custom shapes.

Grinding Between Centers: In this process, the piece is braced on each end by centers. A cylindrical grinder produces the most accurate of all grinding techniques by shaping the outside of the piece to tight tolerances.

Key Terms:
Turned Ground and Polished (TG&P) – This is a finishing process that creates extremely straight round bars by turning, while extreme accuracy is achieved by grinding and polishing.

Boat Shaft Quality (BSQ) – In this type of shafting, straightness of the bar is key to preventing wobble and misalignment issues that can significantly reduce shaft life. There are tolerances and finishes required to meet BSQ standards.

Pump Shaft Quality (PSQ) – This type of shafting is used primarily in rotating industries. Tight diametrical tolerance requirements and straightness give minimal vibration and decrease wear.

Bearing Quality (BQ) – This bar doesn’t have requirements regarding straightness, length, or finish, but has custom diametrical tolerances.