Machines for surface preparation of concrete and or paint removal including traffic lines, cross walk markings, directional arrows, and stop bars on concrete and asphalt surfaces and other hard surfaces, namely, grinding machines, diamond pointed grinders, substrate removal machines, namely, scarifiers, [ shot blasters, ] metal cutters, earth moving machines, namely, scrapers, scalers, namely, machines for de-rusting, de-scaling, de-slagging, removing old paint, stress-relieving weld seams, roughening or bush-hammering, needle scalers, namely, for de-rusting, de-scaling, de-slagging, removing old paint, stress-relieving weld seams, roughening or bush-hammering, separators, namely, dust separators, vacuum cleaners and dust control machines in the nature of vacuum cleaners and power-operated polishers and the parts and fittings for the aforesaid machines, namely, cutters, such as, replaceable pads for grinding, cutting or otherwise shaping concrete or other hard surfaces, drums, namely, replaceable pads for grinding, cutting or otherwise shaping concrete or other hard surfaces, flail shafts, Flail shafts have loosely mounted cutters on them and are thrown forward with centrifugal force that causes the removal or hammering of a surface, [ resin bonds, namely, for attaching replaceable pads for grinding, cutting or otherwise shaping concrete or other hard surfaces, ] and diamond cup wheels, namely, replaceable pads for grinding, cutting or otherwise shaping concrete or other hard surfaces and abrasive disks for power-operated sanders and power-operated grinders