On 19 Jan 2007 11:02:23 -0800, "
wrote:

Hi Prometheus

The problem with the bi-metal blades is to many TPI and not enough set
on them for sawing wet wood, they'll bind up and do just not work well
sawing wet wood I found, the once or twice I tried sawing wood on my
saw with the Bi-metal in place, also most BI-metal bands are wider than
thicker than the wood bands, they need more power and bigger wheel
sizes.
One other thing that does make a big difference is the saw speed in
metal sawing or wood sawing, where the wood sawing blades feed at
approx. 10X the speed of steel blades, as speed goes up so does the
friction and heat, but if you can find some bi-metal bands that do have
the 3 or 4 TPI with a good wide set than it might be more economical to
use one of those.

Speed may be a big factor, now that you mention it- but TPI doesn't
really need to be.

There were two common tooth sets that I've used in steel fabrication-
2-3 and 3-4. Each used an alternating tooth count, as I'm sure you
can guess by the designation, 2 tpi on one inch, and 3 on the next.
The 2-3s gave a fairly rough finish on metal, but would be pretty good
for wood, and IIRC, they had a fairly good set to them- I do recall
turning off the coolant and sawing large oak beams a couple of times
for things like rebuilding the loading dock after a careless truck
driver managed to rip off the bumpers, and building heavy shop stands.
It was a mess to clean the chips out of a saw with a coolant tray, but
it ripped through those massive beams like they were paper.

That being said, they *were* wide and thick- you've got a point there.
The ones I've used had a kerf of .063", and were 1.25" wide. That
1/16" kerf did not reflect the simple thickness of the blade- it was
due to the set of the teeth. The blades themselves were .032" thick,
and the rest was set. Just for comparison, the carbide toothed blades
had a kerf of over .125" Even if they were sharper, that's still
quite a lot more material to remove.

But you've got to have some pretty big wheels in the bandsaw to run
those suckers- perhaps my thinking was incorrect when I assumed that
Lennox makes smaller versions for other saws. I think, but do not
recall for certain, that they do make similar blades with a thinner
band for the smaller cut-off saws, which are not that different from a
vertical wood bandsaw. Then again, my somewhat hazy recollection (the
smaller cutoffs were secondary only) is of 3/4" wide bands with a
slightly finer tooth count- perhaps 5-6. If that's the biggest bite
they've got, they may not work for resawing- but in any case, I'd
still go for the bi-metals over carbide bandsaw blades in a heartbeat!

Thinking back on this made me recall one other thing about bandsaw
blades I never really considered in the wood shop. The Lennox
bi-metal blades were "self sharpening"- that isn't to say that they
stayed perpetually sharp, but rather that they required a much lighter
feed pressure and slower band speed when they were installed new for
the first 10 cubic inches (in steel) of the material cut. Ignoring
that break-in procedure reduced the life of the blade by almost %75.
I don't know if the same logic applies to wood bandsaws, but it may be
worth a little investigation. Hard to say how a guy might slow down
the band speed with a saw that has only one speed, but it's certainly
not difficult to reduce the feed rate for the first (100?) cubic
inches of hardwood cut, and it might help the blades last longer and
cut better.