[Oblarg]

Originally Posted by MichaelBick

What is the problem with hex stock?

It's a pain to sand down if it's too big (and it often is too big), it's more expensive, and not every team has access to a hex broach and arbor press.

Past that, you still need shaft collars or set-screws to hold a hex hub in place. You need nothing to hold a clamping bushing in place except for the bushing. In general, set-screws are terrible and failure-prone and I do not use them when I can use clamping hardware in their place.