Happy at the way things are coming together I found this..
...wondering where it went I was horrified to find it goes on the end of the swinging arm pivot, the bolt goes through this
then the swinging arm, holding everything together.
And I mean everything!
Fortunately I had put the bolt the wrong way through the pivot point, so off came the nut and on went the plate. What does it do?
The bracket is for the bottom screw on the chain gaurd, which is almost ready for a top coat.