I had to punish one of my settlers, the stubborn [censored] wouldn't just take my word when I tried to convince him time and time again to NOT sleep in my shack. I knew he was trouble, from the very start.. I'd find him loitering around when he should have been working, and he had a general [censored] face 24/7, I knew he despised me regardless of me providing him with food, water, shelter, electricity and protection. So I shot him in the forehead with a .44 point blank.
He didn't lose his head. I dragged his limp corpse outside to the rain and undressed him of his earthly belongins, then I tried to severe his limbs with a hooked pipe wrench to no avail. So I just ended up dumping the trash outside of my settlement perimiter for the carrions birds to feed on.
Short answer, no.. Haven't been able to severe limbs off of my settlers.