Another way to look at it is by making a 8-blade 1" cutting diameter BH.

With this you would have:

Cutting diameter = 1"
Cutting Surface = 4"

The damage (cutting surface) is almost twice as much as the other heads that were talked about but the hole would look almost identical to a 4-blade 1" cutting diameter BH.

Would this BH by twice as good as other BH's? NO! Because all the damage (4" of cutting surface)isbeing done in a small area (cutting diameter).

With this being said all damage (cutting surface) is not the same. Again, you need to know where that damage is occuring (cutting diameter).