A few years ago, a co-worker and I were trimming out an 1893 townhouse in Washington, D.C.'s tony Georgetown neighborhood. On this high-end job, all the joints had to be tight and the miters perfect. The job got me thinking about better ways to measure angles, especially inside and outside corners. Eventually, after some tinkering, I came up with an easy-to-use protractor that I thought worked better than any other — but if you think having one really good idea is an easy way to fame and fortune, keep on reading.

While we worked on the Georgetown project, I was troubled by the slow process of measuring the corners with a T-bevel and protractor, converting the measurements to a saw setting, and making trial cuts. I wanted a better measuring tool.

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