Dillon self-centering Jaw Forming Rings, or Jaw Boring Rings, attach to the front of jaws without tools so installation is fast and simple, and set-up times are slashed. Use of this device will provide a jaw surface true to the machine centerline, reduce set-up times, and increase up-times for running machined parts. They provide uniform pressure on jaws for a more consistent bore on large-diameter chucks. Read more