Hi Lou,
Great to hear from you. I think I originally did post a McMaster-Carr parts list, but it would have been posted at the Jag-Lovers forum, since I did this work before the Jaguar Forums even existed. You might find the part numbers in the jag-lovers.org archives, but I think I describe the parts well enough in my phototurorial that you should be able to easily find the parts at the mcmaster.com website:
Welcome to Jag-lovers - Members Photo Viewing Page
If I were building a compressor now, I would not bother with the steel ball - I would just use a stack of heavy washers as other guys have done. In our area, the Tractor Supply Co. stores carry some very nice large washers that are about 1/8 inch thick, so a stack of 6 or 8 of those would serve nicely as the "thrust device."
Please let me know if I can answer any other questions, and please let me know how your project goes! Cheers, Don