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