How to Change Planer Knives in a Delta 15 Inch Planer


Woodworkers use planers to smooth rough wood and to uniformly reduce the thickness of a board. Delta 15-inch planers handle stock up to 15 inches wide and 6.5 inches thick, and offer two different feed rates: a rate of 16 feet per minute for finish planing, and a rate of 30 feet per minute for rough planing. The planer removes up to 1/8 inch of wood with each pass by means of three knives attached to a rotating cutter head.

Step 1

Unplug the planer. Remove the screw located at each corner of the top cover, then remove the cover.

Step 2

Loosen the two large screws on the left side of the planer. (The first screw is located in the center of the pulley cover. The second screw is directly in front of the first screw and connects the pulley cover to the head assembly.) Pivot the motor assembly to the front.

Step 3

Take out the three screws on the top which were exposed when you removed the dust chute cover. Remove the chip deflector underneath to expose the cutter head.

Step 4

Turn the cutter head with a piece of scrap wood until you can access the locking screws located under the first planer knife. Remove the locking screws, locking bar and knife blade. Repeat this step with the remaining two blades.

Step 5

Clean any debris from the cutter head slots. Put the locking screws, locking bars and new blades back in the cutter head. Tighten the locking screws just enough to hold the blades in place.

Step 6

Place the Delta knife setting gauge on the cutter head, with a knife blade centered underneath. The blade ends should just touch the bottom of the gauge. Turn the hex screw located above each knife end to raise or lower that end of the knife to the correct height. (Turning the screw counterclockwise lowers the knife and turning clockwise raises it.) When you have finished, make sure the locking screws are still snug enough to hold the knife in position, then repeat this step with the two remaining knives.

Step 7

Tighten the locking screws completely once you have adjusted all three knives to the correct height. Tighten the screws at the ends first and the screws in the middle last. Remember to tighten the screws for all three knives.

Step 8

Replace the chip deflector and screws, then replace the top cover and screws. Return the motor assembly to its original upright position, and tighten the two large screws on the side of the planer.

Things You'll Need

  • Adjustable wrench
  • Scrap wood
  • Delta knife setting gauge
  • Hex key


  • "The Art of Woodworking: Woodworking Machines"; Pierre Home-Douglas; 1992
  • DeWALT ServiceNET: Delta 15-inch Planer Instruction Manual (PDF)
Keywords: Delta planer knives, change planer knives, change planer blades

About this Author

Etienne Caron teaches English to speakers of other languages and has been writing for Demand Studios since 2009. He graduated from Westfield State College in 1993 with a bachelor's degree in regional planning.

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