comments say the following so take your pick. Use a 15/16 not 24 its much firmer, 1/4 ” Un. Bunnings don't have them. Fasteners Australia do and get 65 mm plus washers to pack them out on the puller. High tensile of course. That thread isn't 1/4inch. Its fking 6mm metric 1/4 inch is 6.35mm.