Counterweight test bar for headstock alignment

[Claudio HG]

The lathe pictures indicate that you have a fairly small lathe in which case the lathe will be deflecting. That will affect the relationship twix theory and practice. That is a large and heavy bar for a small lathe. Free play in the bearings will also cause discrepencies with a heavy bar.

The bed of the lathe has a geometry that should hardly let it twist and moreover deflect (see attached picture). The calculated deflection with a force of 200N (eq. to 20.38Kgf or 44.93lbf) exerted in the middle (between the feet) is far less than 0.01 mm (0.000394") while it could twist by ~0.03 mm (0.00118") under a torque of 1000Nm. So I don't think the bed of the lathe could deflect of any meaning amount for that small weight (the whole bar weigh less than 6Kg (<13lbs)).
However thank you for the hint.