The Fechino Files: Speed Square

Words: Steven Fechino

Steven Fechino

Last month I discussed carpenter’s framing square and how it can be better utilized by reading the tables and scales found on the square for the masonry industry. The speed square was invented in 1925 by the Swanson Company, but today everyone seems to have a version of the speed square. The speed square is much simpler than the framing square. However, it is very useful for a few tasks we perform every day.

Speed Squares today typically come in three sizes. The standard 7-inch aluminum speed square is perfect for the saw table because it will not rust. It marks an 8-inch concrete masonry unit (CMU) almost perfectly across the 7-5/8-inch side when making material cuts (designed at 7 inches because carpenters can mark 2- 2” X 4” studs’ side-by-side at the same time). Most people simply use the speed square to mark 45-degree or 90-degree lines to make proper cuts. 

The inside of the speed square has 1/8-inch and ¼-inch interval scribe slots that will allow the saw person to squarely mark out the small openings and outlet cuts square with the bottom or the top of the CMU. When given the cut list, the mason just needs to let the saw person know where to pull the marks from (top or bottom of the CMU), and the speed square will quickly give square measurements without the need to pull a tape before marking the unit.

It is important to note that Kapro Tools, Johnson, and Dewalt all have slots better suited for a carpenter’s pencil than a number 2 pencil. This note is important only when you need to be very accurate, as when you cut marble or granite. The 7-inch speed Square will fit into a side work belt pouch and is convenient when needed and typically out of the way when it is not.

The next speed square I wanted to mention is the 12-inch model, way too big to put in your pouch but an excellent tool when making field markings at a saw table for larger units such as cast stone panels or 12-inch CMU. The scales are generally the same, depending on the manufacturer. Some manufacturers have conversion tables, and others have aluminum note pads for noting a series of dimensions. My 12-inch Speed square is a saw bench item.  

The favorite speed square that I have used is the 5-inch, this fits in a pouch or a back pocket, but when you need it, it is perfect. I have used the 5-inch speed square to easily mark the ends of the cored brick at 45-degrees to make what appears to be a solid end unit.  It is also useful to make your saw jig for the angled cut. Sometimes, you cannot find matching solids when you do small projects for friends and cap the end of a rowlock.

The uses have been basic, but here are some useful additional uses for the speed square. Check the accuracy and blade square on your saws with the speed square. Always unplug the saw first before attempting to make accuracy checks. My friend “Three-Fingers Ray” taught me this. 

Check to see if your saw blade is plumb with your table. Simply put the wide portion of the speed square on the table and put the opposite leg against the saw blade. This will either be touching at the bottom and the top of the blade, indicating that it is plumb or a gap at the top or the bottom indicating that an adjustment must be made.  

Another use for the Speed Square is marking out perfect circles. To mark circles, simply decide on the radius or the circle's diameter and determine the circle's center point. If you decide on diameter, simply divide that distance by two, and then you will have your radius. If possible, set a nail or a screw (pin) at the center of the desired circle. Then, take the innermost cut out of the speed square and set it on the pin.  Using the desired radius at one of the scribe marks, take your pencil and spin the square around the center pin of the circle to complete marking a perfect circle. 

When cutting marble, an old trick was setting the saw, saturating the stone, and pulling the saw backward to make a clean cut. If you need to make a short cut 12-inches or shorter, the speed square can be clamped to the cut material and makes a perfect saw guide. Just make sure you put the clamps on the far end of the speed square, so you do not get them in the way of the saw…just sayin’.

When cutting coping head joints on the horizontal section of stairs transitioning to the angled handrail going down the steps, the speed square will easily allow you to compute the angle of the head joint cut.

Simply take the speed square and rest the wide section on the top of the horizontal coping with the pivot at the point where the angle changes. The hypotenuse of the speed square is in degrees and will tell you the pitch of the angled coping. 

The head joint cut against the horizontal coping will be the same degree as the pitch but on the opposite side. Do both sides independently from each other as sometimes you can be two or three degrees off from side-to-side. This will assist you in giving the proper cut.

Honestly, I will probably use my speed square to mark square cuts more than anything. It is just good information to know additional features when you need them.

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