a rotatable shell cutter member for cutting a hole in large diameter and thick wall plastic pipe . the shell cutter member is rotated and advanced with a positive predetermined lead against the plastic pipe and it first forms a hole in the plastic pipe by cutting and retaining a coupon therefrom and it further progressively enlarges the hole to a diameter equal to or slightly greater than the overall outside diameter of the shell cutter member . the chips initially cut from the plastic pipe in cutting the coupon are discharged upwardly and inwardly of the shell cutter member above the coupon being cut and , when the shell cutter member with its cutting edge in constant cutting engagement with the pipe begins cutting a continuous chip cut , it is also discharged upwardly and inwardly of the shell cutter member . the cutter blade for cutting the plastic pipe is detachably secured to the body member of the shell cutter member so that it may be easily removed and replaced or resharpened and cleaned when the situation requires such action . a drilling machine powered by a compressed air motor , electric motor or gasoline powered engine may be used to rotate and advance the shell cutter member although hand operated drilling machines with positive feed advance may also be used .