Getting the Smoothest Possible Cut

The cutterhead speed and feed rate combine to give you a certain number of cuts per inch (cuts/inch). Generally, as the cuts per inch increase, the planed stock becomes smoother. To raise the number of cuts per inch, increase the cutterhead speed and decrease the feed rate. To calculate the exact cuts/inch, use this equation:

You'll also find your planed stock gets smoother as you take shallower cuts. A shallow depth of cut does not lift the wood grain as badly, and it reduces the risk of chipping or tearing out hunks of wood.

To get the smoothest possible surface on your planed stock, reduce the depth of cut to 1/64" or less on the last pass through the planer. Increase the cutterhead speed one to two letters and decrease the feed rate to SLOW. If the planer slows or stops during a pass when the feed rate has already been adjusted to SLOW, turn off the machine immediately. Lower the table and remove the stock. Try the pass again with a shallower depth of cut. If that doesn't help, try a slower cutterhead speed (Mark V mounted thickness planer only).

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