An apparatus for coating samples or small quantities of internally and externally threaded fasteners includes a powder feed, an induction heater, and dust collection system. A reciprocating, magnetized holder engages a friction drive to rotate a stud in front of a spray nozzle. In another embodiment, a nut sample machine includes a reciprocating powder spray nozzle mounted on an air cylinder and a water cooled support block for the nut. In a third embodiment a hydraulically controlled gate is sequenced with the reciprocating powder feed, providing a continuous coating operation.