Preventing fuzzing
September 10, 2011 | 7:00 pm CDT

Q: How can fuzzing when machining basswood be prevented?

A: To understand why wood fuzzes, we need to look at some of the fundamentals of machining. When a knife enters the wood, it has a choice of cutting the fibers or pushing them over. The knife will choose whichever one is less work. Basswood is naturally a weak species, so it is more likely that the knife will push the fibers over (resulting in fuzzing) rather then cut them off. Fuzzing tendency is increased if the knife is carbide, if the knife is dull, if the feed is very slow, if the depth of cut is small, if the wood is higher than 6 percent MC, and if the wood is a weak species.

Obviously, the cure is to use HSS knives, sharpen knives often, feed aggressively with reasonable stock removal and avoid wetter lumber. In the extreme cases, prior to final sanding, the wood can be coated with a sanding sealer (or wash coat or sizing). This finish coats the fibers and stiffens them so that they can be easily sanded smooth.

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About the author
Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.