We've been sawing a lot of big walnut the last week or so using the .055 blade. The sharp life veries from 500 to 1000 bf. Not nearly as good as when we were sawing hard maple. The main reason is the dirt and rocks picked up by the cork-like walnut bark. The debarker just can't get all the way to the bottom of the bark. Also, often we're sawing into and out of the bark as we're fishing for a good opening face.
But they are tough! I'll be sawing along and hear a ZIPPP! I know I've hit a rock. Sometimes the size of a pigon egg. Yesterday I was sawing a larger but short walnut log - say 30" dia. x 6' long and was down to the heart saw when I heard Zip, Zip, Zip.. Yep. three 20d nails about 3" from the heart. I changed the blade but could only find a few metal boogers on a couple of teath.
