Thrust force or feed force of a CNC mill is measured to predict the maximum chisel point drill bit that that the mill can support. Software commands LinuxCNC to advance the mill into a scale until following-error from the z-axis servo motor exceeds a threshold.

A viewer warned of column deflection. All deflections were tilting back; there was no measurable lateral deflection. 0.5″ above the spindle nose .001″, 4″ above the spindle nose (middle of the head’s face plate) .005″, and 19″ above the spindle nose (at the back and top of the column) .018″ (or about 0.05 degrees.) 1 thou sounds good, but the head is low when measuring against the scale. Put a long drill bit in, and column-head-tool total may be worse than the .018″. Yours is a great suggestion and deserves more investigation.

Following-error video.
Testing PM25 kit with Leadshine Easy-Servo motors video.
PyMachining Python module GitHub page
Metal Cutting Theory and Practice (book)