Internal spiral groove forces positive clamp arm rotation both in the clamping and unclamping motions. Clamps swing into position, then clamp straight down. These swing clamps swing into position, then clamp straight down onto the workpiece for direct downward pressure. When releasing the clamp, the arm swings out 90 degrees for easy removal and placement of the workpiece. The internal spiral groove forces positive clamp arm rotation both in the clamping and unclamping motions. These clamps are designed to be used in robotized production lines where robots use nut runners. The tapped end of the clamp arm allows for installing a clamping tip. The body and shaft are made from SAE-4140 alloy steel. The clamp arm SAE-1045 alloy steel. Parts are heat treated with black oxide finish. Parts ending in R have a clockwise clamping direction, part numbers ending in L have a counter-clockwise clamping direction.