I have a 4" air operated chuck that I would trade you for the collet draw bar if your interested. The jaws open and close with air and has a 2 1/4" back plate on it so it screws right onto your lathe.
Did you machine come with any other hardware? Wrenches, paper work, etc? I have an owners manual and can get you a copy if you need it, but I think you can also find it on line.