justplainbil

Just Plain Bill

Kerf

Imagine yourself the man on the street taking a survey. If you were to ask a random group of pedestrians the meaning of the word “kerf”, how many of them do you think would know the definition?

It’s a little word buried in the treasure trove of useful and useless knowledge I’ve acquired during my seven decades of living.

I’m taken back to a time when I had the opportunity to teach woodshop for an eighth-grade class in my very first year of teaching. I’d been leading playground programs in several of the more rural and agricultural parts of my county, and, as I’d been interested in transitioning from youth work to teaching, this opportunity came up. I’d completed my student teaching and welcomed my group of 20 eighth graders on day one of the school year.

(A note on the class size: I was assigned a self-contained class of 20 students, five students each from the “bottoms” of the other four classes. The reasoning behind this strategy was that by relieving the four classes of remedial work, the rest in the other classes would flourish. More in a later post on the results of this controversial “experiment.”)

In addition to teaching all the core subjects to my eleven girls and nine boys, I was asked to offer a woodworking class. I did know a little about the craft, having been taught by an uncle who was an experienced shop teacher. Fortunately, my uncle had introduced me to what’s called the kerf, the amount of wood that is cut away due to the width of the saw blade. (It’s also what ends up as the sawdust.) So right off the bat, my class and I were spared a common problem that can occur while woodworking, best illustrated in the following true story:

The minister of my church told me about the time he learned about kerf. He was cutting some wood, using the piece he’d just cut to measure the succeeding piece of wood. When he’d cut all 12 pieces of wood, he noticed that each piece he’d cut was just a tiny bit shorter that the preceding piece, only about 1/8^th of an inch, but it resulted in his next 11 boards being just a tad short. Do the math and you can see how much shorter that last cut piece was compared to the very first. Not good!

So if I’m ever asked the definition of a kerf by that man on the street taking a survey, in a trivia contest, or even on Jeopardy, I’m ready!