It’s Brewer again. Betcha y’all wondered if I was coming back, but wonder no more. Here’s a little handy method for setting a post to stretch a fence out exactly perpendicular, or square, to an existing fence or a straight property line.
Let’s suppose you have a 100-foot tape measure. The longer your measure, the more accurate you’ll be. In this case, a 100-foot tape will allow us to set the post 80 feet away, at the most, from the existing fence. The method is called the three-four-five triangle. If you’ve done a lot of construction, you’re no doubt already familiar with this, and if that’s the case, this post is not for you. I’m going to assume all this is new to you, though.
Pick the place on the existing fence where you want the new fence to intersect it. Tie a string there close to the ground, or drive a stake and tie the string to that. Measure off 80 feet of string and tie that end to another stake. Now tie a another string to the second stake and measure off 100 feet. Tie the loose end of this string to the fence, or another stake on the fence line, 60 feet from the first stake.
Now draw the strings tight and drive the stake there. This will make a triangle 60 by 80 by 100 feet, the proportions of which are three, four, and five. This will always create a right triangle, a triangle with one 90-degree angle.
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The 80-foot length is your new fence line, and the vertical line is your original fence or property line and represents the “3†portion of your triangle. Divide that 3 into 60 feet and you get 20 feet. This, then, is the multiple for the other two sides. Four twenties are 80, and five twenties are 100. So if your short size was 15 feet, there are three whats in fifteen? Five, of course. So four fives are 20, and five fives are 25. Easy, right?
If your new fence is only, say, 40 feet, you still may want to stretch your string out for 80 feet, if you have room. This will increase the accuracy of your measurement. Now, get out that post-hole digger and that fence stretcher and let’s build some fence!
