High-Speed Steel T-Slot End Mills Use these end mills for general purpose work in most material, such as aluminum, brass, bronze, iron, and steel. They're often used to create slots in machine tool tables, indexing tables, and other workholding surfaces. Lathe Chuck Jaw Nuts. 80/20's e-commerce shop is where you can browse and buy T-slot aluminum profile extrusions, fasteners and accessories for your full project build. Shop 80/20's industry-leading offering of T-slot profiles, fasteners, hardware.