I've only been running my WM since 2003, but can't say that I've seen any blades I would really call a hardback. The better quality blades like WM or 'Monkeys' that I have used are true alloy steels and not the simple 'carbon steels' that I think of as being "hardbacks". None the less, the point I was trying to make about selecting blade thickness, is use the thickest blades that don't show premature cracking problems on your mill the way you operate it. I have seen some sawyers that leave the blade running during the gig back. Others, like me, only run the blade when cutting.
As I said before, the thicker blades seem to stay sharp longer and do less waving during the cuts. They seem to track straighter through knots as well. They do require a little more HP because of the wider kerf, but not all that much more. I set most of my blades at .019 to .021 to reduce cutting HP required. The harder the wood, the less set I use, same goes for dryer wood. I reduce the rake angle as well with harder woods. I change the rake more with change in hardness than I do the set.
I also set first and then sharpen. I seldom recheck the set after shapening due to having to remove the burr. When sawing softer woods like Yellow Popular, I may sharpen twice between settings, and they will be full gullet passes. On very hard stuff like Black Locust or dry Hickory, I may touch up the edge 3 or 4 times between settings. It has to be sharp to track straight in hard stuff.
If I know what I will be cutting ahead of time, then I tend to customize the rake and set to the wood type. I also have 5 common setups I keep on hand for regular sawing.
You said you have had a few mistakes while sawing, Hitting metal in the log or on the mill makes setting much tougher to do well. The teeth seem to have a 'memory' that they creep back to after setting. I will often set and sharpen a 'metaled' blade and then use it to open a log ( 4 or 5 cuts ) then will pull it back off the mill and check the set. It is pretty common to find a few previously dinged teeth have shifted 4 or 5 thousand out of place. Another setting after the short run seems to fix the problem.
I learned a lot about how blades cut, the importance of blade profile and hook angles after I started sharpening my own. There is a lot of bad info about the subject floating around in various forums. Theories are nice, but take time to do some test setups yourself using different sets and hook angles on the same log. Try setting a few at .017 or .035 and see what they do in a given log. Don't be suprised if they both seem to have some of the same symptoms of problems. It will be the differences in their problems that you can learn from. Then you can use that info to troubleshoot future cutting problems.
Rick
