Essentials of woodworking

by Ira Samuel Griffith

—Take into consideration the direction of the grain in planning the relative positions of the members. Make due allowance where shrinkage is likely to be considerable.

As far as possible, plan to have the members join face to face. Face sides are more likely to be true than are the other two surfaces and therefore the joints are more likely to fit properly.

Make all measurements from a common starting point, as far as practicable. Remember to keep the head of the gage, and the beam of the trysquare against one or the other of the faces, unless there should be special reasons for doing otherwise.

In practice it is sometimes advisable to locate the sides of a joint by superposition rather than by measurement. Laying out by superposition consists in placing one member upon another and marking upon the second member the width, thickness or length of the first. [Fig. 143]. Usually, it is found possible to locate and square with knife and trysquare a line to represent one of the sides of the joint. The first member is then held so that one of its arrises rests upon this line, and a point is made with knife at the other arris. The superimposed piece is then removed and a line made with knife and try-square—not thru the mark of the knife point but inside, just touching it.

Fig. 143.

Fig. 144.

Where several members or parts are to be laid out, cut and fitted, it is of the utmost importance that the work be done systematically. System and power to visualize—that is, to see things in their proper relation to one another in the finished piece—make it possible for men to lay out and cut the members to the most intricate frames of buildings before a single part has been put together. Lay out duplicate parts and duplicate joints as suggested in [Chapter VII], [Section 62]. Where several joints of a similar size and kind are to be fitted, mark the different parts to each joint with the same number or letter as soon as fitted that no other member may be fitted to either of these. [Fig. 144]. On small pieces, such as the stool, it is possible to aid in visualizing by setting up the posts in the positions they are to occupy relative to one another, marking roughly, as with a penciled circle, the approximate location of the mortises, auger holes, etc. The members may then be laid on the bench and accurately marked without danger of misplacing the openings.

While the knife is used almost exclusively in laying out joints, there are a few instances in which a pencil, if well sharpened and used with slight pressure is preferable. To illustrate, suppose it is desired to locate the ends of the mortises in the posts. [Fig. 144]. To knife entirely across the surfaces of the four pieces and around the sides of each as would be necessary to locate the ends of the mortises, would injure the surfaces. Instead, pencil these lines and gage between the pencil lines. Those parts of the pencil lines enclosed by the gage lines—the ends of the mortises—may then be knifed, if desired, to assist in placing the chisel for the final cut.