How Low Should Feed Rollers Be Set on a Wood Planer?

Most planers set the feed rollers about 0.020 inches (0.5 mm) lower than the cutterhead’s knife arc. This is a common factory‑specified setting and provides enough downward pressure to feed the board without causing dents or snipe. 

What this means in practice
The feed rollers (infeed and outfeed) must sit slightly below the lowest point of the cutterhead knives. This ensures:

Consistent traction so the board feeds smoothly.

Proper pressure to keep the board flat against the table.

Reduced snipe, because the rollers hold the board level as it enters and exits the cutterhead.

Why this height matters
If the rollers are too low relative to the cutterhead:

The board may stall or slip.

You may get chatter or uneven thickness.

If the rollers are too high:

They can press the board too hard into the table.

You may see roller dents, especially in softer woods.

You may get snipe if the board lifts into the cutterhead.
(Woodworkers often note that excessive infeed roller pressure can cause marks or dents.) 

How to verify your setting
Most manuals recommend using:

A gauge block placed on the table under the cutterhead.

A 0.020" feeler gauge to establish the knife’s lowest point.

Then adjusting each roller so it just touches the gauge block at that reference height. 

This ensures both ends of each roller are level and correctly positioned.

Summary
Standard roller height: ~0.020" (0.5 mm) below cutterhead knives.

This setting balances feed pressure, prevents slipping, and minimizes snipe.

Always confirm your specific machine’s manual, but 0.020" is a widely used and manufacturer‑supported value.