Shopsmith 510-520 Pre-1986 Table System UpgradeMark V Model 510 to Model 520 ProFence table system upgrade provides new extruded table rails, a more versatile rip fence and direct reading rip fence scales for your Model 510 machine 8 new extruded rails for your Model 510 worktable and extension tables offer added rigidity and precision over your tubular Model 510 rails and allow the use of the new, larger ProFence New larger 24 1 2" long x 1 3 8" thick rip fence includes a single T slot on its top