This jig can cut the heel contour and drill the coordinator rod holes while maintaining a constant angle. On the left there is a router on a rocking cradle and on the right is a horizontal drill. Both are mounted on a cross slide. The cross slide moves either tool in position as it is needed. The cross slide effectively creates a horizontal drill by moving the spinning drill bit into the heel. Frank Rotella built one out of wood. See pictures here. Frank's jig is similar to to first one I built which is described in an article here.
Left side view.
Right side view.
A neck mounted on the jig.
The rocking motion of the cradle holding the router begins cutting at the depth of the tension hoop.
The bit is not a router bit, but a quarter inch mill.
I use a dial indicator to measure the movement of the cross slide to set up the next cut at the correct distance.
I take a measure from the bottom of the flange to the top of the tonering.
The next cut goes to the measure I made to the bottom of the flange.
The third cut is for the extension that goes under the flange.
I set up the shaper table to the correct depth of cut.
The flange cut is done.