Warren in Lancaster, PA
David, you thought I was picking out pictures to suit my preferences? Really? There is no need to pick. All of the 19th century mortise chisel illustrations I have ever seen had single flat bevels. All of the 18 and 17th century examples also. It would be quite a shock to see something like you are suggesting.

I looked at your "Tooltique" references to Sorby mortise chisels. Right on the page it says he used a water cooled wheel to "refurbish" the tools. So the "factory grind" might just be the Tooltique factory.

I have been interested in mortise chisels since 1973. There were no bloggers at that time. I never saw the Blogger type grind (small secondary bevel long shallow bevel etc.) until after there were bloggers.

Here is a picture from 1667: