Abstract: A percussion welder includes a single acting main cylinder having a ram extending through both ends of the cylinder mounting a spring loaded chuck on one end of the ram and an adjustable return spring on its other end.An automated version includes a hollow ram for the main cylinder through which a stud to be welded is blown from an escapement in a vibratory feeder bowl. The escapement has two spaced guide rails which receive the studs in a single column and a block which slides transversely across the end of the rails to pick off a single stud and move it into alignment with a gush of air which blows the stud head first through a tube to the hollow ram. A chuck having a stationary and a movable clamp is mounted on the opposite end of the ram. An actuator is disposed adjacent the chuck and opens the chuck to permit the stud to pass therethrough and at the same time places a platform beneath the chuck to prevent the stud from exiting the chuck more than a selected distance.