The seller was helpful and exceeded my expectations. I usually only buy online from Amazon.com, but Google's Trusted Stores feature was just as good.
1/3 hp motor sheave 2.25 x .50 fixed
Fixed 1/3 hp, ctv0, bw3500/01-4000/02
Buy this part and as many parts as you like and pay only $9.99 shipping, within the Contiguous United States.