For starters many saw blades centers are not flat. They may be hollow
ground and you would end up distorting the blades. Most are not designed to
crosscut and leave a smooth bottom unless your are using a rip blade and are
going with the grain. A good dado set is precision matched so that the
bottoms of the cuts will be even. This is not likely to happen with common
blades and especially if one of the blades has ever been sharpened.


"Tom Lewis" wrote in message
...
Some 40 years ago when I was in high school the shop teacher would stack
regular saw blades together to make dado cuts. Why shouldn't that be
done?

Tom