Hello Bruce,
I bought the encoder on e-bay for $29.88. It is not longer available from that supplier. I did a quick search on ebay (you can check further), but I think this is the same one:
Omron E6B2-CWZ1X 2000P/R Rotary Encoder New in Box 1 Year Warranty | eBay
Make sure it says 2000 for the encoder count. I have included a link below for the encoder spec sheet as well as a document from another Acorn user that used this encoder on a lathe cnc conversion. It contains some useful information on how to integrate with Acorn.
The encoder pulley is from: https://sdp-si.com/
My apologies, I sent you the wrong file for the encoder pulley. Check the folder again. I added the correct files.
Encoder Info: Dropbox - Encoder - Simplify your life