Steering wheel knob

This is my steering wheel knob (or brodie knob) project for car (or boat)

I needed this to increase my capacity to maneuver my city car during the parking, as I had a small accident on my left hand. It worked very well, despite its simplicity.
I decided, in fact, to avoid bearings (not really necessary due to the limited number of turns it makes)

Here the list of the metallic parts: (all sizes in millimeters)

1 bolts M8 (80 x 8) (hexagonal head)
3 nuts M8 (6 mm thickness)
4 washers M8 (ext. diam. 15 mm.)

2 bolts M3 (20 x 3) (round head)
2 nuts M3

I added several versions, choose the model which correspond better to the section diameter of your steering wheel.

Edit 27/04/16: Added a new larger knob, if you need one (better grip, in case you have an heavy steering, like on a tractor). If you choose to realize this one you should also replace the main bolt, always a M8 but 100 mm length. The jaws remain the same.