fig5 referring to fig3 and 6 dies 16 are mounted within the die carriers 15 each die 16 is mounted within an opening in the die carrier 15 so that it may move radially either toward or away from its respective housing section dies 16 are restricted to radial movement by the walls of the openings through die carriers 15 as well as by pins 20 which fit into slots 19 the radial travel of each die 16 is limited by pins 20 which extend from die 16 into slots 19 in die carrier 15 dies 16 have two curved faces one which is concave and one which is generally convex the concave faces of the dies are gripping faces and have approximately the same curvature as the pipe to be gripped the gripping faces of the dies have ridges or teeth which run parallel to the axis of the annular gripping ring to reduce slippage between the dies and the pipe as the gripping ring rotates the pipe any suitable type of texturing or knurling may be used on the concave face of the dies to enhance the grip of the dies on the pipe on the opposite convex side of dies 16 are smooth camming surfaces 17 a cam 24 is mounted in each housing section behind die 16 the camming surface 17 of die 16 faces cam 24 the surface of cam 24 which faces.