I can just grab a piece of tool steel and go stand in front of the grinder for a while, but I was wondering if there is a simple elegant, not over priced tool to do the job. Ring groove will likely be 1.1" give or take.
********** Seems the old school round boring bar with square broach and set screw might be the best tool for this job. Atleast I can pregrind two or three HSS bits the same for this if I wind up doing a bunch of them.
Now about face trepanning a recess that butts up against a shank diameter. For now I have been using a hand ground brazed carbide inside threading tool. It no longer looks like a theading tool and has relief on one side for the smallest diameter of the recessed area.