Nothing beats having the right tool for the job. If the only tool you have is a hammer, everything starts looking like a nail… and that can be hazardous to your project’s health! The word ‘tool’ doesn’t have to mean things like hammers and screw drivers, it can also include Measuring Tools. Measuring Tools are often overlooked but extremely useful and using the right tool for the job is extremely important. For example, you wouldn’t measure the thickness of a piece of paper with a ruler, or determine the weight of a car using a bathroom scale.
I found myself needing to measure the angle of a roof line then cut a piece of wood to match that angle. How would you do it? Protractors are used for measuring angles but one from your days of elementary school won’t cut the mustard here. Well, I ended up making a tool that will mimic the roof angle and allow me to transfer that angle to my work piece. And the best part may just be that it cost $0 and made completely from some scrap wood and a bit of hardware kicking around the NESIT shop.
The pieces you see here are made from 3/4 inch plywood. They were already ripped to about 2 inches wide, although the wood width for this angle finder project is not important. Actually, no dimensions are really that important! We are only interested in an roof angle measurement. Notice the two holes, those will be used as a pivot point for this angle measuring tool. The pieces were cut to length on the power miter saw and the one radius was created via the sander.
Here’s how the parts are assembled. The square portion of the carriage bolt is hammered into the wood to keep the carriage bolt from spinning. The wing nut is used to tighten or loosen the assembly. However, it is best to leave the wing nut tight enough so that the pieces can pivot with a firm force.
You may be wondering what that radius is for. If there was a corner present, it could stick out past the outside edge of one of the legs which would prevent the leg from lining up against a piece of trim on the house. This phenomenon can be seen in the next photo where the corner of the board is poking out below the bottom edge when the angle finder is closed. Luckily though, the tool wouldn’t typically be used in such a closed orientation.
The below photo shows how the assembly opens, pivoting on the carriage bolt. The angle measuring tool still wouldn’t be used in such a closed orientation. This photo shows the tool open about 45°. The intent is to hold the long leg up to the trim on the the side of the house, then adjust the shorter leg to match the roof angle. The wing nut is then tightened to lock the angle. The tool is then aligned to the piece of wood to be cut, a line traced using a standard pencil, then the board can be cut with a saw… following the line.
With this tool, there’s certainly a chance that the angle could change between taking the measurement and tracing it to the work piece. For that reason, I made some protractor reference marks on one of the legs. When the corner of the other piece is lined up with an angle mark, the outside edges of the tool are at the corresponding angle. The intent isn’t for this to be precise, but a general ball park for the user to understand if the angle changed between measuring and marking.
So how did I know where to make those angle indication marks? That is a great question and it has a simple answer: I used the trusty rafter square. No doubt you’ve used one to make a 45 or 90° mark on a piece of wood but it is much more useful than that! It can be used to find a bunch of angles. There is a corner of the square marked ‘pivot’. Line this point up with the edge of the wood. Then pivot the square so that the same edge of the wood lines up with a number on the scale. That indicates the square’s edge is at the corresponding angle in relation to the wood’s edge. See below, lining up the pivot point and the ’20 line’ with same edge of the wood creates a 20° angle. I used the rafter square to set the angle of my new tool, then marked the angle with a pencil.