Q: We are having a new problem for us. When we plane narrower pieces of lumber, we have a wavy surface, with lots of defects. Wider pieces are fine. Thanks for any help.

A: When a piece of wood is fed into a planer, the piece is held firmly between the bed plate (a big hunk of metal that is the foundation of the machine) and the pressure bar. Each time a piece is fed into the planer, it wears the bed and the bar. There would be more wear in the center sections than on the edges, as most pieces will contact the center area. (Actually, we always suggest that pieces are alternated from side to side to distribute the wear more evenly from edge to edge. Feeding diagonally into the planer will also do this, but not as well.)

After there is considerable wear, when you put a narrow piece into the center section of the planer, the piece will no longer be held firmly but will be free to jiggle or vibrate. This movement is causing your defects. (There is also a likely increase in the chance that a piece will fly back out of the machine as it gets worn. Pieces flying out will come out slow enough for you to see them, but too fast for you to get out of the way!) In short, it is time to call a repairman to recondition your machine; do not delay.