.Unused but needs to be cleaned up. Instead of a scribing pin, the MG-1 uses a precision turned, hardened tool steel (Rc 62) cutting disc. Beveled on one side to 30 degrees, this disc is very sharp. The beveled face runs adjacent to the fence. This arrangement allows for a constant wedging action, always pulling the fence tight against the work piece - a very important feature for accurate joint layout, particularly in wavy or pronounce open grain woods.