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Hand tools Metalworking
Woodworking Moretofollow |
LayoutAs a layout tool the try square is used whenever it is necessary to draw or scribe a line at right angles to any given surface. The handle of the try square must be kept in contact with as much of the surface as possible, for if the handle is off in space it will have insufficient bearing surface to insure a line that is square. Checking a try squareThe accuracy of a try square can be readily checked by means of lines drawn with it. Place the handle of the try square against the edge of a board having a true edge; that is, an edge that is straight. Draw a line across the face along the blade of the try square. Then turn the try square over and draw a second line. 1f the try square is accurate, the lines will coincide; but should the try square be out of square an error will show. Laying out anglesThe framing square is most commonly used in laying out angles. By using the graduations on the body and tongue of the framing square, it is possible to lay out any angle. The most common angles the woodworker uses are those required in the construction of polygons — figures or shapes having three or more equal sides. The framing square is used, for example, to lay out an angle of 60 degrees. The 12" mark on the tongue is lined up with the edge of the stock while the 6 15/16" dimension on the body is also brought in line with the same edge as shown. The line drawn along the body when the framing square is in this position meets the edge at an angle of 60 degrees as indicated. The laying out of any of the above angles is done in the same manner, using the measurements for the tongue and blade in the above chart to obtain the angle indicated. The angle in every case will be produced by the line drawn along the body of the square. A line which is drawn along the tongue wil] be the complement of the angle shown, which is the difference between 90 degrees and, in this case, 60 degrees; the difference is 30 degrees. The use of a wood fence attached to the framing square is of considerable help when marking off a number of like angles. Such a fence is made of a strip of wood having two saw cuts large enough to permit the tongue and body of the square to be inserted. The face can be held securely in any position by means of bolts and wing nuts. As a layout tool, to draw lines at an angle other than 90 degrees, or exactly a right angle, to any face, edge, or end, the T-bevel is frequently used.
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