I'm hoping some one knows about old Union Mfg Co. lathes chucks. I have a 6" one marked U-770 3 jaw scroll chuck.The jaws are also Union Mfg Co. with no.906 marked on them. No. 2 jaw has 2 teeth broken off of the scroll. Are these a special thread pitch to that chuck or can they be replaced , and can you get them from any place?