John,
Following your suggestions, I loosened/removed the blade and zeroed the upper wheel, laying a straight edge across it to monitor the tilt as I adjusted the tracking mechanism.? Then I re-tensioned and adjusted until the blade was just above the rim flange.? The blade still was misaligned enough to scrape the guard.? I noticed that tightening the mechanism's center bolt also affected the tracking so I used an interative approach -- adjust the bottom screw, tighten the center screw, check the tracking, loosen it and re-adjust the bottom one, and so on.
FYI, I became curious about how much the frame itself is bending on that axis.? I didn't expect much, but what the heck.? I again used my laser pointer, attaching it to the top of the frame and aimed it down.? There is a lip near the bottom where I could place a machinist ruler to check the deflection.? From no-tension to fully tensioned, the beam deflection was pretty small -- something on the order of .02 inch, .5mm.? ?I just realized that this could be a way to set the blade tension.....with some characterization, anyway.
I also loosened up the blade guides and found that worsened the tracking problem.? Moving the bottom blade guide down also exacerbated the tracking problem.
Other than fooling around with the tracking mechanism and blade guides, I haven't modified the band saw.
The blade isn't the newest in the world, although it is NOT the one that came with the saw -- not long after getting the saw I got a bimetal blade for it.? If the problem is (somehow) related to the blade, would there be any other symptoms to look for?
