Here is a very slim jig designed to hold small blades that must be sharpened with a very low angle :
http://www.labellenote.fr/file/homem...affutage_0.JPG
http://www.labellenote.fr/file/homem...affutage_1.JPG
http://www.labellenote.fr/file/homem...affutage_2.JPG
So the long bottom part is a leftover cut of a garden door hinge, and the top jaw is a piece of aluminium door threshold.
The bolt is stuck with metal epoxy.