First, order 10 Ripper 37, 144", 7°, .042", 1 1/4" blades, and 10 of the same blades in 10°. Use the 10° for very hard, frozen, or petrified wood, use the 10° for pine, dry oak, etc. I used a brand new 7° blade on a giant piece of Purple Heart wood, and it was pretty impressive, just how quickly it went through the log!