For Larry NeIll..

Ann Arbor Machine Co. built hay balers (hay presses) in the 30's and maybe even earlier than that. I have a picrure of two balers being pulled by Hart Parr 18 -36's with P.T.O.'s.

In the mid. 40's Oliver bought the Ann Arbor Machine Company of Shelbyville, Ill. and that is how they got into the baler business. Oliver continued to make the Ann Arbor style of balers into the early 50's, then they re-designed the big balers and also came out with a line of smaller balers.

Oliver built the 50 60 62 620 520 720 710 smaller type balers, and the 8 100 101 102 103 and 104 larger type of balers. From the mid. 60's to the mid. 70's White Motor Co. sold one Oliver tractor line and two Oliver implement lines, (balers & corn pickers) to other non-related companys. The baler line was the last to be sold, and Hesston was the company that bought it. The Hesston 4500 baler was the first baler that they built using the Oliver design. They are also the only company of the orginal above mentioned three that is still in business building Oliver designed equipment.

Hesston has owned the baler line for over 30 years, so I don't think you could get parts from them for a Oliver baler.

I can still get most arts for my 620...for the knotters at least. I believe the 620 and 520 knotters are the same. I have been using my 620 for about 5 years now, save for last year. A friend loaned his 720 that has a lot more capacity so I used it last year. They put out nice tight square bales, but like a lot of older balers, don't try to bale anything too wet or you'll be talking to yourself!
Parts from Agco are pricy...best to keep an eye out for used spare parts!

Good luck, Larry NE IL