is integrally formed with a larger diameter portion 19 a stair stepped groove or rabbet 21 extending from adjacent the larger diameter portion 19 to adjacent the eccentric spindle 20 formed on the body 11 to accept support arm 30 support arm 30 is secured to the tubular body by a plurality of socket head cap screws 43 43 u2032 and 43 u2033 of varying lengths that attach the support arm body 30 to the body 11 each of the socket head cap screws is further secured in the support arm body 30 by retainer ring 45 which is inserted in a groove 45 u2032 formed on the interior surface of the support arm the support arm body 30 provides a spindle 31 which fits into the space formed by a journal 28 at its distal end journal 28 is formed with an eccentric or non circular profile 22 on its proximal end to mate with spindle 20 on the tubular body 11 to prevent rotation of the journal 28 in either direction allowing the hole opener to be used in either direction journal 28 provides bearings 27 and bearing races 29 to facilitate rotational movement of cutter shell body 25 on the journal 28 each of the cutter shells supported on the multiple support arms may be provided with hard facing in a.