CASTLE NUTS

Similar to a slotted nut except that the slots of the castle nut are cut into a cylindrical portion of that is equal in length to the slot depth and slightly smaller in diameter than the hex width. The slots are for the insertion of a cotter pin to secure the nut when used with a drilled shank fastener. The slotted and castle styles are both interchangeable, with the slotted design now the preferred style.