Drawing from memory here, over the last year I recall some threads on chucks/jaws not running true, and some of that discussion came up also on threads related to lathes/spindles/manufacturing tolerances.
Currently, I have 8 chucks. 5 Teknatool and 3 Hurricane HTC models. I have had the SuperNova2's for years now. A couple months ago, I purchased a new set of bowl jaws [4" outside diameter-3" + inside diameter dovetail jaws] and put them on one of my SuperNova2 chuck bodies. I noticed a good bit of runout, where with the other jaws on the chuck it had run true.....obvious to me it was the new jaw set.
I actually used this set of jaws on a cherry burl I purchased from a turner at the Virginia Symposium back last November, and found a hidden branch inside the burl, all rotted out, which left me a hole right in the middle of that 15" burl that was over 2" in diameter, and went about 10" across, and made the thing structurally a failure where it was located......that was $25 down the tubes!
I noticed the jaws were giving me more runout than I thought was acceptable, so today, I put that chuck on the lathe, and took my Serious Toolworks Ultimate Gouge to the jaws to true them up. I thought that particular gouge would be best because the hardness of the metal on that gouge is 68 to 70 on the Rockwell scale, just below the carbides. That gouge peeled off tiny curls of metal and allowed me to true up the jaws and make a much improved situation.
I could tell that whoever cut those jaws into the 4 sections did a fairly sloppy job, as two of them sat a bit proud of the other two jaws. I am a firm believer that even in the same brand, that one can detect differences in the tolerances at times from one run of manufacturing to another. I am a guy that likes precision, and I am sure that many other turners on this forum are like me, in that they want to have a quality product when they drop the hard earned $$$ for a piece of equipment.......even an accessory like a 4-jaw chuck.
I would encourage turners who have runout in their chuck to examine them carefully, and see if it is the jaws that are the problem, or the seating of the insert that is causing it. If it is the jaws, then a good carbide tool, or even a good quality gouge can help you true up a jaw set if you are so inclined. I ran the lathe at about 500 rpm, and VERY CAREFULLY put tool to the face, inside and outside of the jaws and took tiny metal shavings off the jaws until it ran true. It was a bumpy start for sure, but got better as I went. Safety shield is so important as well as protective gloves........those little metal shards can penetrate skin or eyes and can be like a difficult splinter, which can cause pain and be hard to remove, so SAFETY FIRST! I hope this helps some folks out there who are not happy with runout in their chuck jaws.