24 each clamping actuator includes a cylinder 41 41 39 in which is movably disposed a piston unshown attached to a piston rod 42 42 39 at the end of each piston rod is affixed a cam actuator 44 44 39 each cam actuator includes an actuator surface 45 45 39 engageable with the cam surface 29a 29a 39 of one of the clamps 28 28 39 when the pistons in the cylinders 41 41 39 are actuated to their upper positions the actuator surfaces 45 45 39 of the cam actuators 44 44 39 do not contact the cam surfaces of the clamps 28 28 39 however when the pistons are actuated to the lower positions the actuator surfaces of the cam actuators do contact the cam surfaces of the clamps 28 28 39 to force the clamps toward one another in the mating direction the clamping actuators 40 40 39 are preferably pneumatically operated the block 26 clamps 28 28 39 and clamping actuators 40 40 39 basically comprise the clamping system of the joint forming apparatus 10 the base 20 also includes an arm 32 as shown in detail in fig2 a the arm 32 includes a mandrel actuator mount bracket 34 and mandrel guide 36 a mandrel actuator 37 is secured to the.