Defective blades? I know many on this board rave about rotary carpet blades from Harbor Freight because of their great price, so I bought six packs (45mm) and split them with my sister. After using the first blade one time, I tossed it out because it cut worse than the blade I was replacing. Then I thought it was probably just one defective blade, so I tried another and it was just as lousy at cutting. Not buying blades from them again!