Headstock fatigue rupture prevention

[Claudio HG]

Oh ok, you have a point about vibration dumping, and actually I have to think something about that, but I was first primarily concerned about safety and double-triple check that I did not miscalculated something.
About unbalances if a mass of 1Kg (2.2lbs) is held in, say, a 4 jaws chuck, off-center of 70mm, and put in rotation at 1000rpm, that mass would generate an oscillating force of 768N or equivalent to the force exerted by a weight of 78Kg (172lbs). I think this would be an insane unbalance for such a small machine that a machinist should avoid by placing some sort of counterweight, or reducing the speed. With half speed (500rpm) that force would be 19.6Kg (1/4) (43lbs) and still would cause a lot of vibrations because it would represent 1/10 of the estimated final whole weight of the lathe.
Still, a force of 192N (19.6Kg) would make that 9mm shoulder to vibrate at an amplitude of some fraction of tenths of microns, while the whole clamp would flex/vibrate at an amplitude of 1.2 microns (0.047thou) ...theoretically.