How would I sharpen on my new T-7 a 3/8" corner chisel? The bevel is on the inside and since there are two opposing angles, which jig would I use and what angle approach to the grinding wheel would I use?
Corner chisels cannot be sharpened with a jig.
They have to be done freehand, on the corner of the grindstone. Carefully align the bevel to the grindstone and avoid pushing the exact center into the corner of the stone. You need to get all the way into the corner, but you have to do it gently.
Just an update on sharpening my sorby 3/8" corner chisel. I tried sharpening it freehand as you suggested, and I made it worse. I ended up spending $4.50 to have it professionally sharpened. It was worth it. Otherwise I sharpen all my chisels and turning tools with my T-7 and my results are flawless. Thanks again for the help.