Bought this hole saw to replace my 4" Lennox which I destroyed after just cutting two 4" holes in fiber cement siding in our new home . for outdoor lighting pancake mounting boxes. I've already drilled six holes in fiber cement siding with this disc at low speeds. I also ordered a Starrett shank with a carbide center drill as I wasn't sure if my Lennox shanks would be compatible. Note. The Lennox arbor works great with this hole saw.