SonomaProducts.com wrote:

On the multi-router using the standard method for cutting tennons the
tip of the cutter is creating the shoulder and the side of the cutter
is creating the face of the tennon so the length of cutter that can
extend from the collet is the absolute max length of tennon that can
be cut.

Understood. That necessitates a bit long enough to reach the shoulder -
but if the tenon is cut with multiple passes, the cutting length need
not equal the length of the tenon.

That being said, many (not all) user of multi router use it for
mortises and use floating tennons exactly because the tennon cutting
is a little less acurate and consistent because of the nature of the
cutting geometry with so much bit length involved..

Yuppers, and if the MR is reasonably stable (and I assume it is),
accuracy should be actually be improved with multi-pass cutting because
there is less stress on everything.

I suspect that multi-pass cutting is more of a hassle - but I also
suspect that bearing life would be extended by taking lighter cuts.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/