The Sliding T-Bevel Square is an essential tool for laying out, checking and reproducing inside and outside angles. It is also known as a False Square. The Sliding T Bevel Square is composed of two elements connected with a carriage bolt (¼ x 1") and wing nut, which allows its blade to pivot. 

The Sliding T-Bevel Square can be used to duplicate an existing angle, or set to a desired angle by using it with any number of other measuring tools such as a protractor, or framing square.

A simple and effective traditional tool. One advantage of using the printed version is that it won't rust. The blade was printed with 50% infill and the body was printed with 15% infill using brims to prevent warping. 

Along with this square, I have modeled a Center Finding Square that accurately finds the center of round and cylinder bars and stocks. 

https://www.printables.com/model/258736-center-finding-square