IMPROVED TRI-SQUARE PROTRACTOR

摘要

An improved combination square set is provided. It has a square head, a center head, a protractor head and a blade. The improvement is the blade which can be a grooved L-square rule, a grooved T-square rule, a grooved try square and a grooved flat straight rule, so that the improved combination square set can be used to measure and mark quadrants on round stock, the angle of a drill press table and angles on a flat board.