I may have a large set of collets for your machine. Do you have a picture of your spindle and collet? I picked up a Gorton a long time ago, and after realizing the lead scews and ways were worn out, I parted it out. I still have all of the collets for it. I think up to 7/8" and down around 1/16". I was going to ebay them but it'd be much easier just selling them cheap to you provided they are what you need.