South Bend milling machines have a 30 taper; and also a provision 
to attach large face mills directly to the aprox 3" wide spindle
face.  This offers a good improvement in potential
rigidity and shortened tool overhangs for a small Bridgeport
sized machine to run larger face mills and  shell mills.

I needed a "large" face mill to run some castings on this machine.
Commercially available face mills are expensive, would need to be
extensively modified to fit the SB spindle face; and are not 
available in the "ideal" size i needed of 4-1/4" cutting circle.
Another issue is that while the SB is a rigid macine for its
size, and equipped from the factory to run good sized face mills, 
there is the problem that the stock motor is only 3/4HP. 
My requirements for the mill were "few" teeth to accomodate the
low HP, positive axial & radial rake, again for the low HP, and
for reducing induced stress in the large machine areas of the
castings, a small lead angle (75 deg) to "soften" the cut, and
a toolbody built to fit the face of the SB mill spindle.