You should be able to get them from Axminster. I don't know if they have dealers with spare parts in the US. I did break some teeth on the pinion gear, the one that is used to tighten things up, on one of my Vicmark chucks years ago, and Craft Supplies had spare parts. There is another gear, kind of a spiral out from the center gear, that the jaws seat into, and that may be more difficult to find.
robo hippy