March 8, 2011

Framing square
Photo by Jim Ruen
You can use a framing square to calculate inches of rise per foot into degrees of slope.

I picked up a new framing square the other day, as my old one was getting increasingly hard to read due to corrosion. Of course, when you buy a framing square, you get a great deal more than you may ever use, for a framing square is truly a carpenter’s computer. Knowing how it can be used may help you decide what to look for in buying one yourself.

My use of a framing square, like my use of a computer, has always been relatively simple, checking board ends for a square cut and marking boards and beams for cuts. Just as I’ve never done complex calculations on my computer, I have never framed rafters for a roof. However, embedded in the side of my framing square is all the information needed to cut and bevel rafters and more. And that is just the beginning.

Framing squares differ in the number and type of information presented and can differ substantially in price, running only a few dollars to $50 or more, depending on whether they are made of aluminum, steel or even stainless steel. Mine was relatively inexpensive at $14.95 and made of double-weight aluminum, yet it offers me straight edges divided to 1/8 inch, 1/10 inch, 1/12 inch or 1/16 inch. Tables convert inches to tenths of a foot, as well as provide decimal conversions for common measurements from 1/32 inch to 15/16 inch and inches of rise per foot into degrees of slope.

Next week, we’ll take a look at some of the countless ways a framing square and these tables can be used in your home and shop, even if you don’t plan on building a house.

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