I wonder if this fixes the usual problem with electronic edge finders: fine chips adhering to the part being measured (or the finder itself) and giving false indications. I haven't tried measuring the resistance of the dust or fine slivers, but it should certainly be considerably greater than the resistance through the machine column and vice, so this approach might be a perfect way to avoid those false readings. In fact if the slivers are very small, it might even fail to detect a contact where a sliver is trapped between part and tool. That would give you a positive indication that the part or tool need cleaning. Interesting project!
All surfaces must be clean or you won’t know what you are contacting.