On Tue, 14 Sep 2004 03:08:46 +0100, Andy Dingley
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

I hyave used an old non-tunsgten blade to cut steel. In too-thick
steel it gets very hot and starts to warp. When it cools down it's
straight again. So you check the blade, and find that it's OK when
cool.

The wandering is probably because the blade is not parallel with the
foot(?) on the saw. So if you cut with a fence, the saw wanders. You
then have to push sideways to maintain the cut and bingo.

http://codesmiths.com/dingbat/photos/sawblade.jpg

Friend of mine showed me this at the weekend. It's a 7 1/2" CMT thin
kerf sawblade, used once in a Hitachi C78U. Both of these are pretty
decent kit and shouldn't be causing problems.

As reported, the blade was used once for sawing some MDF (and it was
in the right way round). The cut wandered and so my friend was trying
to steer it back into line. Sideways rubbing led to the overheating
you can see, which is hardly surprising on a thin kerf blade.

But why should the overheating be confined to two opposed spots,
rather than a ring ? Is there some mounting-induced warp that I've
not noticed ? Runout (by eye) seems negligible.

************************************************** ***
I know I am wrong about just about everything. So I
am not going to listen when I am told I am wrong about
the things I know I am right about.