John Martin wrote:

I've often thought about making up a toolholder for my shaper that
would allow mounting a bit in line with the ram movement axis. Â*You
could use, say, a 3/16" square bit and feed it into the corners.

Something like this:
http://www.motor-manufaktur.de/werkstatt/10_keyways/en_index.html

And yes, you could quite easily get the 0.05mm tolerance.


Nick