The title of the March 2023 edition of this column was “Sweep the Floor,” referring to the value of maintaining a clean working area and the inevitability of generating waste material in pursuit of making useful and beautiful objects. Looking back on that essay, I now think that I overlooked some important lessons. The waste that we generate comes in many sizes, ranging from hefty cutoffs to sanding dust that’s finer and more hazardous than most visible household dust. For example, when you sand hardwood with 400-grit sandpaper, the resulting dust is in the range of about 1 to 50 microns, with most of it in the 5 to 30 micron range. For reference, white all-purpose flour has an average particle size of 50 to 100 microns, though the actual variability is considerably wider.
As Norm Abram routinely reminded us, safety glasses are an essential defense in the shop, blocking large flying objects but typically ineffective for sawdust. Your N95 mask will capture something like 95% of airborne particles larger than 0.3 microns, which are much smaller than most sanding dust, and would be certainly effective against much coarser dust generated by a hand- or power saw.
Sawdust is inherently dangerous, and I’ll leave it to our resident medical professionals to spell out the risks. Particulate size varies by species, and the size of dust particles is only one of the issues when we think about the hazards that sawdust presents. We know that species vary in the degree to which they irritate skin, eyes, upper respiratory tissues, or digestive tract (if swallowed). Some are allergens, others carcinogenic, and most represent ignition risks.
Reflecting on the 2023 advice to sweep the floor, I want to modify my conclusions. It’s one thing to shovel up large cutoffs or plane shavings and quite another to sweep vigorously and launch tiny dust particles into the air where they might enter the nose and mouth, eventually making their way south into the larynx and beyond. Sweeping dust without an effective, tight-fitting mask is a questionable practice, as is vacuuming the floor with a standard shop vac without a HEPA filter or cyclone. The standard current advice is to capture dust at the source to the greatest extent possible. Better still, we’re well-advised to follow the lead of the TWIG group and use a hand tool in favor of a power tool. Prefer a card scraper over a sanding block. When practical, reach for a handsaw before a circular saw. Both saws will create sawdust, but the dust from the power tool is more likely to become airborne. Sawdust will happen, but you do have some control over the severity of the risks it presents.
Low-dust methods have other advantages as well. The chance of a traumatic bloody injury is much small with hand tools than with power tools. The same is true for the chance of dramatic errors. I can’t speak for you, but I can make big mistakes much faster with a table saw or bandsaw than with a handsaw. Additionally, hearing protection is not necessary with human-powered approaches, and there’s something very attractive about the peace and quiet of these methods. One need not abandon electric power entirely, but traditional methods are very worthy of consideration.
While it’s true that saw dust happens, it does not have to happen all the time.
