Z-axis: Quill vs Knee

What are pros and cons for using the knee versus the Quill for feeding
the Z-axis?

I realize the obvious con of much larger mass and force required and
massive "weight compensating springs" for the knee. On the other hand,
locking the quill will give a much more rigid system.

My mill already has built in DRO. I intend to use the DRO encoders for
the CNC function. The Z-axis is monitoring the knee, not the quill. I
can always switch to the quill but I like to evaluate my options before
digging into the conversion.

My goal is to do the conversion so that I can also manually run the
mill. Although, that could be under joy-stick mode and I let the servos
do the hard work

Bertho Boman
Vinland Corporation
in now too hot Florida