Re: St Roy says
ThomD
>That doesn't work in this case. It isn't exatly twisted, it is folded. Where the transition takes place the section is like an angle iron. So you have some vertical blade, and some horizontal blade, and the folded section is morphed through 90 degrees. The way it works is that you kinda punch the angled section in there, like starting a drywall hole saw, then once it moves back and forth you work it deeper until you can freely saw horizontal. Unlike a fret say this saw can't begin to be turned within the kerf. However a fret saw is a pretty good thing for roughing out DT tails and pins.
There is a good sidebar in FWW 18 with diagrams and explanations. I know that if I tried to post it, it would go over the size count if I did it so it was legible. Maybe someone with a scanner could put it up.
It looks to me as though the easiest way to make one might be to get a very soft blade, or cut a blade in un-HT material then fixture it in a sheet metal brake. For what it is good for, it would probably not need heat treating, or maybe it could be electro heat treated. I have a crafty concept for that...
This isn't some tool for making the DTs in your ebony sidetable, It would be for big boxes, and I have a fast way of doing those by hand, sorta. Or it would be a great teaching aid for getting a lot of sawing/fitting practice without having to sweat out the chopping.