Originally Posted by
Mcgyver
don't understand the Q - are you asking was the set-tru means? the jaws are individually adjustable, you set it to run true (for a particular dia). each time you use it at that dia, it runs as true as you set it. like HuFlung said though, you haven't changed the accuracy of the scroll and it will perform as any other three jaw of you change dia's. imo Bison chucks are ok, not Pratt Burndrd or Rohm, but nice to work with and better value than the aforementioned...eastern European iirc and much better than the junk you see coming from China/India/etc