The term joinery as used herein refers merely to the fitting together of two or more parts called the members. 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 try-square 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. 113. Usually, it is found possible to locate and square with knife and try-square 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 through the mark of the knife point.
Fig. 113. Locating by Superposition.
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 of the most intricate frames of buildings before a single part has been put together. 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. 114. 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. Fig. 115. The members may then be laid on the bench and accurately marked without danger of misplacing the openings.
Fig. 114. Members Marked after Fitting.
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. 114. 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.
In sawing joints in hard wood, the saw should be made to cut accurately to the line. When working soft wood, beginners are often permitted to leave a small margin -about one thirty-second of an inch - between the knife line and the saw kerf. This margin is afterward pared away with the chisel.
In assembling framework and the like, where it is necessary to drive the parts together, always place a block of wood upon the member to be pounded to take the indentations that will be made. A mallet is preferable to a hammer for such pounding.
Fig. 115. Location of Joints Roughly Marked.
Frequently a piece of work will require the making of two or more like parts. To lay out these parts, that is, to mark out the location of intended gains, mortises, shoulders of tenons, etc., so that all shall be alike, the following method is used: (1) On the face edge of one of the pieces measure off with the rule and mark with knife the points at which the lines for the joints are to be squared across. If knife marks would show on the finished surface as scratches, use a sharp pencil instead. (2) Lay the pieces on the bench top with the face edges up; even the ends with the try-square. Figs. 116 and 117. Square lines across the edges of all of them at the points previously marked on one of them. The pieces may then be separated and lines corresponding to the lines just made on the face edges be carried across the face sides of each piece separately, the try-square beam being held against the face edge in so doing, of course.
Fig. 116. Making Ends Even.
Fig. 117. Marking Duplicate Lengths.
In all duplicate work the aim of the worker should be to make as much use as possible of the tool he has in hand before laying it down and taking another. To illustrate, if there should be a number of like parts, each requiring two different settings of the gage, he should mark all of the parts at the first setting, then all at the second setting, rather than to change the gage for each piece so that each piece might be completely marked before another is begun.