I haven't messed around with any of the small or large circular saw blades - yet. But you have to be careful with the newer ones. Many are bi-metal - one type of alloy steel for the teeth area and another type alloy for the main center part. The same goes for many of the modern hacksaw and bandsaw blades.
I have made a lot of small knives from handsaw blades, and the big crosscut saw blades. The crosscut saw blades work well for the classic trade knives, butcher knives, and scalpers. Also for big folding knife blades. The handsaw blades work well for small utility knives, penny knives, and other small folding knives.
I chisel out the profile of the blade I want on the saw blade - slightly oversized. I then clamp it in my vise and tap along the sides to break away the parts I don't want. I then grind the blade down to the final profile of the knife. Cool it often. If it's getting too hot to hold in your fingers, cool it. Ifr it's starting to turn blue - cool it now. After I get it profiled out, I then grind my blade bevels for the edge - sometimes with the bench grinder, sometimes with the angle grinder and a sanding flap wheel. Final edge bevel is done on the belt sander. Sometimes I drill the pin holes in the handle (eats drill bits, even the good ones), but mustly I punch them through and then touch up with a drill.
If you don't overheat the blade, the original heat-treating of the saw blade remains and works great in the final knife. Forging a chunk of saw blade into a knife blade requires the whole heat-treating/tempering process - of course.
Just some humble thoughts to share.
yhs
Mike Ameling
