David Weaver
..I took a picture of my IH sorby chisels - I don't know if this may be the factory primary bevel. Someone horsed it. All of them were like this but some with more use than the others.

With chisels this (a cross section as thick as they are) if they didn't have a shallow primary, they wouldn't be able to get out of their own way in a mortise.

The horse is the "roll" that we discussed a while ago.

A horse will still get you from a to b just fine! (just as bill found dovetailing ash).