I was installing some channel drains with a helper the other day across the head of a concrete driveway. All went well until I started to tie in to a field drain I installed back in the day. We were digging and ran into a piece of oak 2x4 too long and deep to dig up. So I thought I could cut through it with my brand new 14" Shindy w/diamond blade. WRONG. I'm not sure why but I killed that brand new $150 blade in about 10 seconds. A daimond blade will cut concrete,stone, and rebar, but not WOOD!!! The good part is the dealer comp'ed the blade. The bad part is I still have to buy a new one.