How to Balance Planer Knives

Use a postal scale to balance planer knives.

Planer knives are on opposing sides of a shaft that spins at an incredible rate of speed. If the knives are not perfectly balanced, the planer will vibrate, shake or even break up while running, causing bodily injury or worse. When planer knives are sharpened, cleaned or replaced, it is vital that they be balanced. All of the knives should weigh exactly the same before they are reinstalled. You can balance knives with a bench grinder.

Things You'll Need

• 4 millimeter hex wrench
• Postal scale
• Pencil
• Bench grinder

Instructions

1. Turn off to the planer. Take off the dust covers and the planer head cover.

2. Use a 4 millimeter hex wrench to loosen the setscrews holding the knives to the planer head. Spin the head with your hand so that the screws are facing straight up and remove them. Lift out the knives one at a time.

3. Place the knives on the scale. Weigh each one. Write down the weight of the lightest knife and set it aside.

4. Hold the knife with both hands with the sharp edge facing your body. The back of the knife should face away from you. Turn on the grinder.

5. Hold the back of the knife against the spinning wheel. Move it from side to side gently to remove metal from the back of the knife for one minute to make it weigh less.

6. Lay the knife back down on the scale. If the weight is still more than the lightest knife, grind some more off until the weight of the two knives match. Grind all of the knives in the same manner until they all weigh the same. The knives are balanced and ready to be reinstalled in the planer.

Tips & Warnings

• Planers have two or more knives depending on the model. They all need to be balanced.

• Don't attempt to work on planers unless you are experienced or have an experienced operator to help you.