Try D. C. Morrison Company: http://dcmorrison.com/
They bought much of the leftovers from the shutdown of the final Millrite production, and have more parts for them than anyone else does. What is the matter with your pulleys, if I might ask?
D C Morrison is a manufacturing company. They buy the stock and put it on the machines to make what ever part you need. Prices are on the extremely HIGH. $400 for one of the screws is just a little bit high. I remember when I was working they had the mechanic come in and replace the nut and lead screw to the tune over $10,000.00, when replacing the nut would have made the machine just about perfect. Parts are expensive and there is no such thing as OLD STOCK items sitting around on 50 year old machines.