Abstract: This invention relates to a tool for uniformly compressing a non-resilient metal ring to a smaller diameter which comprises an outer hollow receiver provided with a handle for manually holding the receiver against turning, a threaded shaft in the receiver which at its one end within the receiver has rotatably mounted thereon a collet which upon being drawn into the receiver by rotation of the threaded shaft causes the fingers of the collet by engagement with the inner wall of the receiver to move inwardly or toward each other to thereby uniformly compress to a smaller diameter a metal ring mounted in the ends of the collet fingers.