I remove the one nut holding the blade, which takes about 5 minutes, and sharpen it with a bench grinder. I have more control on how much to remove and I am able to balance it. My 18 x 46 tractor's mower deck has three blades. I remove the whole deck before winter because I have a snow blower attachment that goes on the tractor. I have all winter to remove and sharpen the three blades. You might be able to get a replacement blade at HD or Lowes. Check their one-line mower supplies.