Throw this in your pocket when you go to the lumber yard or any other place where you might need to make an estimated measurement. It can actually be reasonably accurate with good calibration. I show in the pattern how to do the calibration. We calibrate the roller to a circumference of five inches.
There are many times when you do not need a measurement down to the 1/8". Maybe you just want to know if a board is wider than six inches. This little tool is handy for those cases.
The tool is so easy to make that you can have two or three around in places where you might need one. People who sew or do other crafts might find one handy also.
Watch the video demonstration to see how it works.
Video Demonstration.
Notice that I cut just outside the pattern line.
Take the roller to the disk sander and sand to the line.
Install the roller on a 1/4" dowel and do a test measurement of a known 5" line. If the roller is still too large then take it back to the disk sander and remove just a small amount. Continue this procedure until you get as accurate as possible. Just don't sand the roller too small. If it gets to small cut another roller and start again.