I bought a used 6" Sears jointer years ago, used it probably 15 years. Then I bought a used Powermatic 8" jointer in almost perfect condition Holy cow what a difference. I guess I didn't realize how much difference a good jointer made until I started using one. Took me a day to carefully dial it in, but its been dead on for the last 5 years. It has straight knives, I've had them sharpened once. Very happy with it. Randy