This strange looking jig is a jig that makes spacers for use with a straight edge. Very handy when it comes to making dados or when using a circular saw to cut boards to length. The spacers are very easy to make. Just stick some ply or mdf up to the fence using double sided tape.Pop a router bit 1/2"or what ever in the collet rout along the fence and you end up with a spacer to use with that particular bit.
This is my version of the clamp and guide along with a spacer to be used with cicular saw. Another spacer would have to be made if I was to use it with the router.
As you can see the timber to be cut or dado-d is sandwiched between the two 2"x1" timbers (my clamp and guide)ready to be adjusted.
As can be seen from these pictures a pratice piece has been used to give an idea of how it all works. Basically the spacer is positioned on a line the guide is then brought up to the back edge of the spacer and tightened and away you go.
This mortice jig is used for 18mm or (3/4") stock once set up to rout the right length slot. It is very accurate and many idetical mortices' can be made. To be of more use it would be better to make a wider slot that could be used with different guige bushes.