I don't think it is so simple. If the material [M] doesn't
touch the housing, there is no axial force - the M rotates
with the screw in place.
This means that the layer will move at different axial speed. The M closer to the axis will rorate with the srew
and advance axially only slowly - the outer layers
will rotate slower and advance faster.
If course there is some mixing between the layers,
further complicating the picture.
Why not just simply measure it ?
Plesae read FAQ240-1032
<nbucska@pc33peripherals.com> omit 33 Use subj: ENG-TIPS