Greetings woodworking gurus. I have a Powermatic 66 (circa '96-'97) that I love, save one perceived flaw. I have used it for years and now that I'm about to build a series of cabinets, I decided I should find out if there's a flaw I need to correct. I use a Freud 8" Safety-dado (SD308) and noticed that whenever I have multiple chippers installed (such as for cutting a 3/4" dado) that there are only a few threads left on the arbor. Very little of the nut can be placed on the threads unless I were to go without the "washer" next to the blade. I included two pictures if it might help. One shows the dado blade in place with the washer as well as a second one without it. I bought the SD at an auction so it didn't come with instructions. As such, I was wondering if you could give some advice on the proper blade and chipper mounting so that I'm left with some threads for the nut. I've always been leery of going without the "washer" since there is one on the left side of the blade. I am always careful to ensure none of the teeth are touching. Thanks a million in advance for your help!