Hex bit to M8 screw

I had a lot of M8 bolts to screw in, and I didn't have an adapter for my screwdriver. So I made one.

Structural integrity is questionable.

V2: Using the original model showed that a) the circular socket was too big to get into a couple of the spaces I was working with and b) the axis of rotation was annoyingly off-centre. So I fixed that.