The latest attempt at knurling using a pinch type tool was realatively straight forward. Unfortunately, while it is self centering as it approaches the workpiece perpendicular to the surface, the fact that it hangs down normally prevents it from entering from the side without hitting the face even though there is a chamfer.
You can see from the way it hangs down that it will hit the side of the wheel rather than straighten up.
Even if it were locked in this position, there is no guarantee it woundn’t hit rather than center.
Bottom line, I don’t know if any of this will work as an automated solution. If you have to position it with the pendant and move inward with the pendant it is the same as just doing it manually. Well, at least you don’t have to turn the handle. cheers!