Rotary tool

Especially before the advent of widespread CNC usage, they were heavily relied upon for contouring via manual skill comparable to a sculptor's.

CNC now provides much of the contouring for die and mold interior surfaces, but die grinders are still very useful for hundreds of cutting needs, from sculpture-like contouring in the absence of CNC, to cut-off of bar stock, to any of the cutting and grinding needs of fabrication, such as in the work of welders, boilermakers, millwrights, ironworkers (steel erectors), sheet metal workers (such as auto body workers and HVAC technicians), to woodworking (especially cabinet making), hacking, and other hobby or business pursuits.

Die grinders are often used for engraving, cylinder head porting, and general shaping of a part.

The cutting may be done in various ways, including: The cutter is usually held in a collet, which is a convenient means of chucking in this application and provides the concentricity needed for high-RPM use.

This prevents the throttle from opening (being pressed down towards the body of the grinder) without operator intervention and inhibits accidental activation.