I've had my Delta planer for quite awhile now. In its lifetime it has had hundreds of board feet of hard and soft wood passed thru its portels. Much of this wood has been some of the hardest stuff on the planet. Mesquite, Quebracho, Vera, Mistol and white Oak just to name a few. I am on the first edge of my second set of knives. As in all planers, knife adjustment is critical, and with these knives it is as simple as tying your shoelace. Knives are sharp enough to shave with out of the pkg, and the locater holes make alignment a snap. Getting four cutting edges for this price makes the whole package a five star unit. I've had my problems with some Delta products, but this isn't one of them. Love the planer and love these knives. Highly recommend.