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    Tame Tearout on the Jointer and Planer





    Wood is an amazing material, widely available in all sorts of colors, with beautiful grain patterns. It cuts easily with small machines and tools—products that are accessible to the home craftsman—and its strength-to-weight ratio rivals high-tech materials. But it is organic, and therefore comes with some strings attached.

    One is movement, and there is no stopping it. The other is tearout. A budding hobbyist soon encounters splintered edges and pockmarked surfaces, damage that grows more obvious when finish is applied. It happens with almost every tool in the shop. The good news is that it can be stopped, in most cases easily.

    Tearout happens when wood is cut and its plant fibers aren’t held firmly in place. There are two main types: One happens when wood is cut across its grain, and the other when the surface is planed. Preventing crosscut tearout is relatively easy to handle once you know what to do (use zero-clearance plates and sacrificial fences), but surface tearout is trickier.

    Jointers and planers can create nasty tearout in wood surfaces, especially when they hit grain that changes directions. Here are some ways to reduce tearout.

      Planer tearout  

    Pay attention to grain direction. On the jointer, the edge grain should run downhill toward the rear of the board.

    On the planer, the downslope should point to the front of the workpiece. (See the image at the top of this post.)

    Cut with the grain as much possible. If you are getting tearout, try reversing direction. Also, try replacing dull knives with sharp ones. Sometimes it also helps to dampen the surface with water before sending the board through.

    Dampening the face of the board softens the surface fibers slightly, making them easier to cut and less likely to tear out.

    Photos: Steve Scott Drawings: John Teatreault and Jim Richey

    Excerpt from Christiana’s March/April 2010 (FWW #211) article “How woodworkers tame tearout”.


    AsaC