Good afternoon, dear guests and subscribers of the "Build for Myself" channel!
Today, I will describe a carpentry marking tool. This triangle is officially named "Swenson's Square" or "Swanson speed square"and was invented by the legendary American carpenter Albert J. Swenson in 1925.
Its functionality is very rich and includes not only linear measurements, but also many nonlinear ones, which I will discuss later. I will also designate functions that for some reason are not described anywhere, but they exist and are actually feasible with this tool.
General characteristics
An isosceles right-angled triangle, in the original design - made of aluminum, on one side along the leg there is a shelf (hard stop), protruding exactly 1 cm in each direction, the thickness of the entire square is 5 mm, thus the total width of the shelf 25 mm. or 1 inch.
Both scales are stamped on both sides in perfect symmetry with each other. Due to the stiffness of the square due to the thickness of 5 mm, it sits comfortably in the hands, does not bend when working.
The square includes a protractor with different variations (from marking rafters and flights of stairs to building geodetic slope), a compass for constructing circles, a level for checking the slope and a thickness gauge for marking parallel lines.
Available in two versions: classic inches and metric.
Functionality
There are both basic functions of a square for a common layman, and professional ones for a carpenter or roofer.
So, the basic functions of the triangle are:
1. Thanks to the rigid stop, a "quick" mark of the right angle and 45 degrees is applied using a square.
2. Accurate transfer of the angle from the model to the product on the scale of degrees.
3. The square can be used as a guide rail for circular saws (conveniently without preliminary marking with a pencil - leaned against, sawed off)
4. Thicknesser function. Scribing notches made in 5 mm increments. serve to mark a parallel line to the end of the product. How it's done: we make an emphasis of the triangle shelf at the end, set the pencil in the recess to the desired value, lead the square parallel to the edge of the product for the required distance.
5. Compass function. An arc or circle is drawn in a similar way. The pencil is set in the notch and the square rotates around its pivot point.
Professional triangle features:
1. Protractor function. Thanks to the notch at the point of rotation of the triangle, by driving in a nail, we can build any corner on the product without displacing the tool.
2. In the original version, a diamond edge is made along the hypotenuse along the ruler, with the help of which it is easy to put marks, notches or slightly hang the bar.
3. Level. Together with the plumb line, the square turns into a level. It is done like this: the plumb line is passed into the recess and the square is set by the hypotenuse on the plane, the level of which we want to know. The zero point is taken as the value on the 45 degree square.
4. Non-linear measuring scales of the square are linked by trigonometric functions, for example - the scale of the angle of the valley and the corner rafter (in the picture above - Scale No. 3).
The angle of inclination of the valley or corner rafter is calculated according to the following relationship between scale # 1 and scale # 3:
Thus, knowing only the angle of inclination of the main slopes of the roof, we are in place, without additionally taking any measurements, we can saw down the valley or hip rafter leg.
5. The grading of the geodetic slope (Scale No. 4) works as follows: for example, we have a given slope of 40% or 4:10 (i.e., the rise is 4 m for 10 m), you need to transfer it to the part:
We set the square close to the workpiece on its hard stop and give it rotation until the end of the product reaches mark 4 on the scale number 4. Draw a line (highlight in blue). The slope of this beam to the end of the workpiece is 40% or 4:10. We can immediately measure this rise in degrees, since the scales №1 and №4 are linked by trigonometric functions tg and ctg. Agree that it is convenient!
In addition, some manufacturers report clamps to the set of the square, which facilitate the work when marking the same products:
The cost of the product varies from 1500 to 3000 rubles. depending on the configuration. At the moment, such squares have already appeared on sale in China.
That's all, if you forgot anything, ask, I will definitely answer! Thank you for attention!
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