On Aug 29, 10:34 pm, "Ivan Vegvary" wrote:
Also crossposted to rec.woodworking

Installing Hardie Plank siding. (Fiber cement combination) Manufacture
states that I should use a special blade. Went to Home Depot, and yes, they
make a special blade. It is simply a carbide tooth blade with with a total
of 6 teeth. 7-1/4 inch diameter.

Can somebody explaing why a six tooth carbide blade would cut any better
than, say, a 24 or 40 tooth blade that I use for lumber? I don't understand
the physics.

Thanks,

Ivan Vegvary

While the 6 (or 4 on the blades I have seen) tooth design does help
control the chip load, I think it has at least as much if not more, to
do with economics than physics. The teeth on the blades made for fiber
cement board while mostly carbide, are poly crystal diamond (PCD)
faced. You may have noticed that that 6 tooth blade cost more than
your 40 tooth wood cutting blade? would you really want to pay 4 times
more for 24 teeth?
I have cut a limited amount of fiber cement with a wood cutting blade
and it worked well enough, but forget about using the blade again for
wood. I have also used a diamond wet saw, which, while messy and not
spectacularly fast, did give a very smooth cut.