Tearout on a planer or jointer

What you see

1. Chips torn out of the surface instead of cut clean, often around knots or where the grain changes direction.

   3 sources agree , sources [1, 2, 3]

Likely causes

Most-agreed first: the more makers name a cause, the higher it sits.

1. Dull or chipped knives or inserts.

   4 sources agree , sources [1, 2, 3, 4]

2. Feeding against the grain.

   3 sources agree , sources [5, 2, 3]

3. Too deep a cut.

   3 sources agree , sources [1, 2, 3]

4. Feeding too fast.

   3 sources agree , sources [1, 6, 7]

5. Knots, or figured wood whose grain changes direction.

   Two sources: Grizzly Industrial and RIKON Power Tools , sources [1, 3]

What to change

Change one thing at a time, so you know which change fixed it.

1. Rotate, sharpen or replace the knives or inserts.

   4 sources agree , sources [1, 2, 3, 4]

2. Turn the board end for end so the knives cut with the grain.

   3 sources agree , sources [5, 2, 3]

3. Take a lighter cut.

   3 sources agree , sources [1, 2, 3]

4. Slow the feed; on a two-speed planer, use the slow speed.

   3 sources agree , sources [1, 6, 7]

Preventing it

1. On figured wood, or where the grain changes direction, take several light passes rather than one heavy one.

   Two sources: Grizzly Industrial and RIKON Power Tools , sources [5, 3]