I have to ask - what are you going to do with a machine that just shirrs?
I did some online searches and had not luck finding even a manual for sale. (Lots of places to get parts lists.)
There is a guy who has an old video on the 451 on youtube.com. If I had not other options, I might contact him. Usually there is an email address or maybe a comment section or some way to get in touch them.
bkay