CTS makes both long and short shaft 500K pots, and many people seem to be unclear what to use in their Les Pauls so I thought this pictorial might help shed some light on the differences between the two and what guitars they are used in. The long pots have 3/4" long threads and the short pots have 3/8" long threads. That is just the threaded portion and does not include the shaft or drum. Originally all Gibson LP's used the short shaft pots, as do the Historic series R8,R9 etc. but then in 1977 Gibson started using the long pots and mounted them inside the control cavity on a metal plate. Even if you remove the metal plate you will still need long shaft pots because of the thickness of the maple cap. After 1977 all these guitars use the long shaft pots, Les Paul Custom, Standard, Studio, Traditional, Classic, Double Cut. These guitars still use the short shaft pots: SG, 335, LP Special, LP Jr., the Paul, Flying V, Explorer, and Firebirds as well as all epiphone LP's. In 2008 Gibson replaced the metal plate with the PCB board and mounted the long pots right into that. The short shaft pots usually use one star washer, one flat washer and a control nut. Another nut can be put on first as a spacer if the short pots are being mounted into a pick guard or control plate. The long shaft pots come with two nuts so you can adjust how far the threads stick through the carved top as it varies in thickness by V & T knobs holes. The nut goes on first, then the star washer, then the flat washer and nut goes on topside. Adjusting the bottom washer will allow how far the threads stick through the wood. You will need at least 3 threads to be able to get the washer and nut on. There are always exceptions and probably a good idea to measure the thickness of the top or length of the old pots if you are not sure what your guitar needs.