pin assembly 10 in accordance with the present invention includes a pin member 12 having a shank 14 and a housing 16 the housing has a substantially truncated cone shaped portion 17 and a cylindrical portion 19 extending therefrom the shank has a central axial bore 18 open at one end 20 and terminating at a shoulder 22 formed within housing 16 a shaft 24 is mounted within the bore 18 for axial sliding movement and a spindle 26 formed at an end of the shaft constitutes a land or edge 27 which serves to hold a pair of radially movable balls 30 in their fully projected position the balls are about 180 degrees apart that is the balls move radially in lateral bores 32 in shank 14 the outer ends of the bores 32 can be u201c staked u201d to reduce the size of the openings 34 which intersect the outer cylindrical surface 36 of the shank 14 and this reduced size opening retains each ball from laterally escaping when the shaft 24 is moved axially to bring a spindle groove 38 into alignment with the balls the balls 30 move radially inwardly so that they do not extend beyond the outer surface 36 of the shank an actuator button or knob 40 is fixed to the.