The copying ring with a diameter of 5/8" is just right for working with cutters up to 15/32" in diameter. You can get it perfectly centred using the fastening screw. Indispensable when working with templates. For gauging routing templates. the copying ring can be precisely centred with centring mandrel 492187. for OF 900, OF 1000, OF 1010, OF 1010 R, KF