Dick, it depends upon which brand of saw you own, the blade screw on the EX and on the Dewalt I believe, have a pivoting tip that will turn when it's tightened against the blade. This stops the blades from bending, when the blade screw is up against the blade, which puts pressure against the set screw. The set screw has to be in the proper position also, so that when the blade screw pushes up against it, it will not be pushing the blade sideways, causing it to break. Personally, I think that it's a really good system, as long as you keep it adjusted properly and you keep the tip of the blade screw lubricated. I've never had any problems with my saw, it runs like a dream, but I do service my saw and keep it clean. All this info came with the saw, it was printed in the owners manual, their a good book to read, lots of tips.
Len