While preparing for a family trip the day after one of the clamping knobs for the cars rooftop bike rack cracked. While the clamping knob holds a regular M8 nut i could have just used a wrench to tighten it i but instead i decided to make a new one.

This is a clamping knob which holds a M8 nut and can be used on a M8 threaded rod.

This is what makes 3Dprinting so cool, being able to make your own spare parts.