Seems like it would work if you were careful not to jam the disk and crack it, but it would tend to fling a lot of abrasive dust onto the ways.
I have mounted a tool and die grinder on the toolpost of my lathe, and cut wood flywheel rim patterns, turning the chuck by hand so as not to smash the wood into the bit (turning on the lathe results in ejecting the flywheel pattern from the chuck generally).
And I recall mounting my bench grinder to a bracket on the side of my mill, and using that to grind with, and that did not work well at all, for a number of reasons, some of which was wheel loading with I think aluminum, and some problems with rigidity.
I would think you would have to slow the table movement on the shaper down pretty slow (if possible), to avoid cutting too fast on the disk.
With the right setup, I think it would work, but protect the ways from the grit.
That is my 2 cents from a rank amateur.
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