If I remember correctly you can cut a piece of bicycle inner tube to fit inside the clamp and thus not mar the steering wheel. Necker
knobs were very popular in the fifty's before power steering was common. It allowed one hand steering witch took two hands in
those days. My '51 Kaiser was very hard to steer with a necker nob until I figured out the steering sector box needed lubrication
now and then. Ah the fun of driving in those days.