No, they should not mar the floor, as long as they are installed according to directions.
Yes, they will work on some angled chair legs as long as the screw is completely seated below the top of the anti-skid pad and the angle allows the majority of the pad to touch the floor.
The pads would work, however you would need to use machine screws (into a tapped hole). These 1" would screws wouldn't work in cast iron.
Yes, but they don't slide easily.
They are not available in bulk at retailers.
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