You may have better luck asking this question on the Old Woodworking Machines Forum. (http://owwm.org/). You may also be able to find documentation in the Craftsman section of the Vintage Machinery website (http://vintagemachinery.org/mfgIndex/detail.aspx?id=222&tab=3). As common as Craftsman tools are in general, I haven't seen too many of those, but they are out there. Good luck.
If all else fails, post a picture of the part in question. The King Seeley era Craftsman machines I have dealt with were generally pretty straight forward. Someone may recognize the solution by the picture alone.