Every year, new tools are introduced. In time, most are replaced by another tool that does the job more efficiently. A few tools, with some combination of efficiency, versatility and practicality, are timeless — in every toolbox for generation after generation. The combination square is such a tool.
The combination square consists of a hardened steel graduated rule and movable combination square and miter head, precision ground with a 90˚square face and a 45˚miter face.
Invented by Laroy S. Starrett in the 1870s, it is an excellent tool for many measurement and inspection tasks. Here are a few:
- Check ends and edges for squareness
- Draw a perpendicular, square and parallel lines
- Check a forty-five degree miter cut
- Set the height of a table saw blade
- Ensure that a table saw miter gage is 90˚to the blade
- Ensure that a table saw blade and miter slot are parallel
- Set up a miter saw for a 90˚or 45˚cut
- Set the depth of cut for a router bit
- Set up a table saw blade at a right angle to the table
- Measure the depth of a dado cut
- Measure height and depth
- Set a jointer fence at 90˚
- Mark a consistent position from one work piece to another
- Check a workpiece for consistent thickness
- Check tennon cheeks to ensure parallelism with the face of the workpiece
- Set a drill press for hole depth and stop position
The available center head is used to accurately locate the center of cylindrical workpiece such a dowel, or a square workpiece.
Also available is a protractor head that revolves a full o to 180˚ with direct-reading angle graduations in both directions to quickly and accurately determine an angle from above or below the blade.
