I am thinking to put some 5/16" hardwood floor on my stairs.
I have to cut off the nose from the 1" ply treads in order
to put the hardwood nose on it.

Some web site I visited suggested to cut the nose with a
circular saw. But I did some cutting with a cheap ($40) Sears
Craftsman circular saw before,and I never cut anything straight,
both horizontally and vertically. I wonder if it would make a
difference with a more expensive one. And I would avoid to use
the circular saw if I can.

rec.woodworking is a good newsgroup for this kind of question.