My friend told me that he went around many shops looking for shaft collar of just the right size but was not successful after a week. This is a friend whom I had tried to convert to an online shopper but he refused.
Well, shopping online, he could look for what he needs in multiple sizes. Stores online offer the full range of shaft collars and I believe no matter what diameter or width he wants, he would be able to get just the right fit.
My friend is afraid of shopping online because of all the negative reports he read in the papers. I think if he takes some precaution and only shop at reputable, secure sites, he should not encounter such issues.