Seems that 3 blades are required to cover all the cases- 24 tooth for thin material, 14 or so for medium stuff, and a coarse one like 6 or 8 (maybe even 4) for the really thick bar stock. My saw doesn't have the blade guard covering the drive wheels; blade changes are quick without it.
Morse blades are good and reasonably priced- Amazon has them
Mark S.
ps the blade will make a sort of musical sound when plucked if it's at the right tension; sounds like an "E" chord on a guitar to me.