To divide a board or sheet of plywood into equal parts:
- Hook a measuring tape or ruler over the edge of the board.
- Extend the measuring tape to the other edge of the board.
- Adjust the tape so the measurement at the edge is evenly divisible by the number of parts desired.
- Mark each of the evenly divisible measurements on the board.
- Repeat at the other end of the board.
- Use a chalk line to connect the marks at each end.
- Saw the board or sheet of plywood along the lines.
Watch this video to find out more.
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Danny Lipford: Your high school math teacher told you how important those math skills would be throughout life. Well if you’re a carpenter, you know how important it is to measure and cut accurately, if not it’ll cost you a lot of time and money.
Joe Truini: That’s right, Danny. Here’s a technique that doesn’t require any math at all, and it allows you to divide a board into equal parts.
Let’s start by taking the ruler off a combination square. And then you set the zero mark on one edge, and on the other edge you pick the number you want to divide the board into.
In this case let’s say we want to divide the board into eight equal parts. And then you simply make a mark at each of the inch graduations. And then you repeat the process on this end, and then you just connect the marks and the board’s automatically divided into the eight equal parts.
Danny Lipford: Now I can see where that would be real handy if you’re cutting, say furring strips or batten strips out of piece of one by six like this. But if you could use the same method on a piece of plywood, that would really be handy.
Joe Truini: Well you can. You need to use a tape measure, and there’s a little bit of math involved, but it’s still really easy.
You start by hooking your end of your tape onto the corner of the sheet, and then you pick a number that’s easily divisible by the number of parts. In this case let’s say we want to divide the sheet into six equal parts. So you set the 60-inch mark right on this edge, and then you make a mark at 10, 20, 30, 40, and 50.
And then you move your tape down to the other end of the sheet, and you repeat the process, again keeping the 60-inch mark right on this edge. Then all you need to do is use a chalk line to snap a line between all the marks, and it’s automatically divided into equal parts.