The blades back/relief angle

[Pabene]

About back/relief angles for our band saw blades.
When I started to cut logs in my band saw mill, 15 years ago, I was surprised that the relief angle was 30° on most all blades. I have experiences from metal shops, (as a tool maker), and the relief angle on tools in such shops are never so steep. I modified the cam in my grinder and started to ground the blades to 16° relief angle. It was an improvement for me. A year later I met a man from a log band saw factory in the Czech Republic. He told us they had ordered a study, at the university in his city, how an optimal tooth and gullet on a blade would look like.
I remember from the report, the relief angle, just at the tip of the tooth, would be 12°. It is what I have on all my blades now. When I compare my blades teeth with circular blades and wider blades for big mills, it looks similar and the cut is now smother and better. I think the blades also stay sharp longer.
I would like to know why there are so few improvements from the manufacturers, on our 1.5" blades, during the last 20 years.

[ladylake]

 
I tried a couple of those steep back angle blades a few years ago, didn't cut straight and couldn't take a nail hit very good.  Steve

[Kbeitz]

That back angle really makes a difference on metal cutting drill bits and lathe and mill cutters.