Step 1: Tools and Materials
- A plastic protractor
- A piece of wood
- Some screws
- A piece of wire or a long finish nail and a hex nut
- Magnetic cabinet door catches (optional)
- A table or radial arm saw
- A rule (and a square)
- An electric drill or drill press and bits
- A countersink bit
- A file
- A pair of pliers to bend wire, or a welder to weld a hex nut to a finish nail
- A level
- A grinder
The photo shows a commercially available angle finder. It reads 360 degrees. A protractor has readings for 180 degrees, but that will be no problem for a reason explained later. While the commercial version is not expensive, it is more fun to make your own.
(The photo is from Lowes.com.)
Step 2: Cut a Piece of Wood
Saw your piece off to be a little longer than the base of the protractor, and so the corners are exactly square. Check with a good square and by measuring the diagonals. These things really need to be very accurately done, or the whole tool will be compromised.
The square is a larger tri-square I have long wanted. See this Instructable for how I made it.
Step 3: Clamp the Protractor to the Wood
Step 4: Fasten the Protractor to the Wood
I chose to locate the screws at 45 degrees on each side of the protractor. Because they are countersunk, the screw heads are slightly below the outer surface of the plastic on the protractor.
I considered painting the wood white or placing paper under the protractor to make reading the angles easier, but decided it was not necessary.
Step 5: The Pointer
Step 6: Finish the Pointer
Step 7: Attach the Pointer
I placed a washer under the pointer. I did not make the head of the screw tight against the hole in the pointer, but made certain it is loose enough for the pointer to swing freely.
Step 8: Calibration Check
See the second photo. The pointer is correctly calibrated. If the pointer did not read correctly, I could bend the nail just a little near its middle to get an accurate reading corresponding to the level.
Step 9: Using the Angle Finder
The commercial angle finder shown in step 1 is graduated with readings for 360 degrees. But, it does not have two parallel edges. I can place my angle finder under or over an angle to be measured. The first photo shows a reading taken from under that angle. The second photo shows a reading taken from above the angle. All you really need to know is how many degrees off of a horizontal or a vertical surface the angle is. The third photo shows the angle finder used with the side as the base for measuring a more vertical angle.
My angle finder does not have magnetic bases like the commercial version does. But, I could easily acquire some magnetic catches like those used inside cabinets to retain a door. If I put two on each side, I could attach my angle finder to a metal surface.