Replacement castle nut and cotter pin for King Kutter rotary cutters. This is the nut that mounts the blade pan to the gearbox, fits 4, 5, 6and 7 cut mowers with 40hp and 60 hp. gearboxes in both 3-point and pull type hitch. This is a flanged type nut that eliminated the washer that was used on early models along with the nut. 1"-14 thread pitch! We sell all of the replacement parts for the King Kutter mowers. If you dont see the parts you need listed please contact us we would love to earn your business. We are listing new items frequently so please check our store often. Part Numbers: 501110 We stock a wide variety of replacement parts for Agricultural Equipment please contact us if you have any questions or if you would like more information.