I just put my new bed extension on my Jet 3520B,dear oh dear what a palarva,bed was on the legs the wrong way around,so there were no threaded holes where I needed to bolt the extension on,so its a case of when you set your lathe up,make sure everything is where its supposed to be,as it took an extra hour to fix the ble--r on,but on a good note I have 48 inches between centres with drive centre and revolving centre and 46 inches between centres with chuck in place,cheers,
Eric.