New fret slotting jig

I use my small Proxxon table saw for slotting fretboards. If you're looking for one and can't find it, the Microlux brand is very similar (exactly the same) and that's carried by for example Micromark in New Jersey. 

I use the saw for few things other than fret slots, for example slotting bridges. But really not much. 

I have a fretting mitre box from Stewmac and some longer scaled boards I've cut by hand because the old jig was a bit weak and wobbly. But doing it on the machine is quicker, more accurate and what's not to like about that. 

First pic shows the old jig, I've used this for all my sopranos up until now. 

But recently I was contacted by a fellow builder asking what blade to use and that reminded me that I'd promised to make a better sled jig. I made a sketch for him but when I made this I made it a bit simpler. The plywood is some old shelf I found in the trash, dead flat and lacquered. It has rails on the underside that go against the edge of the table. 

I pared and planed the rails from super tight to smooth and steady, then I raised a 1.5 mm blade through the plywood base. I put a shim in that slot and set a square against it so I would [theoretically] get the fence square to the blade. But the lacquer caused it to shift since not even superglue grabbed fast, so I had to fix it with a rabbet plane. 

That was easy though and the result dead on. 

But..! Then I changed to the 0.5 mm blade and that one is tiny. It's made for an even smaller saw but comes up 10-11 mm over the table on this one. And how thick was my plywood? I got a bit tired - had I been so dumb that I didn't think of that? Hell yeah, I was dumb. I turned the height screw frantically but it bottomed out before I saw the blade. Darn. But the locking nut on the screw wasn't completely out, I turned that as far as I could get it and again raised the blade. 

Success! It comes up around 1.6 mm, just enough for the fretwire I use. And it works brilliantly.