I have found a good place to get Atlas Lathe parts, I think other places order from this company. They sell you the real parts as the company was Atlas a few years ago. I needed a two step pulley, one company tried to offer it to me for $188, Clausin Ind. charged me $144 with shipping and Handling! The tapper attachment is only $391.08 with shipping etc. You can buy one from ebay for about $600 - $700.
Here is there web site
http://www.clausing-industrial.com
If you need to get a manual for an Atlas lathe, then get intouch with Quaterbore "the person who runs this forum" as I bought a disk that had all the manuals down loaded onto it. So far it has made life allot easier then tring to find parts manuals etc. when I am in a hurry.