center portion being open and receiving by way of fixed mounting as by welding or the like a downwardly inwardly tapered inner surface hollow annular bowl indicated generally at 20 which in top plan view is generally of rectangular form and being wider than the base bowl 20 is open at the center as at 21 and is provided with a tapered inner surface at 34 the annular bowl 20 is segmented into two parts or sections including a pivotable door indicated generally at 31 which is pivoted to the second part or main section 33 of bowl 20 the bowl 20 acts to support on the tapered surface 34 individual slips as at 24 26 28 and 30 the slips 24 and 28 constituting driving slips while slips 26 and 30 constitute floating slips slip 30 is carried on the tapered surface portion of the pivotable bowl door 31 the downwardly and inwardly tapered surface 34 of the hollow bowl 20 is uniformly in taper the upper end of the tapered surface 34 being recessed as at 36 and 38 at circumferentially spaced locations so as to receive rectangular blocks 40 which include a key 42 projecting outwardly from a surface portion or side wall 43 which is parallel to and constitutes an extension of the tapered surface 34 of the bowl vertical bore 44 within the block 40 and tapped and threaded holes 46 within the spider bowl 20 allow the blocks 40 to be rigidly mounted to the bowl proper and to the door 31 via screws 48 the keys 42 fit.