Abstract: A simple three piece machined steel Collet-Spindle Adaptor for angle grinders includes a hat-shaped base having interior threading for coupling with a threaded spindle on an angle grinder. A sleeve extends therefrom and has an interior surface which engages with a collet. The preferred adaptor converts an angle grinder to accept die grinding tools and other similar tools, thereby providing flexibility of tooling, flexibility of application and work area, ergonomics in operator comfort by providing two hand operation, safety in lower operating tool speed, and reduced cost as an additional die grinder and expensive air compressor are not required. Simple machined design allows rapid change over and small size allows easy toolbox storage.