To place the fastenings in each piece of timber so that there shall be sufficient resistance to the giving way of the joint by the fastenings shearing or crushing their way thru the timber.] 1.

_Avoid multiplication of errors by making all measurements (as far as possible) from a common starting point, and laying off all angles from the same line or surface._ Illustrations of this principle are as follows: Before proceeding with other processes, a working face and working edge and as many other surfaces as will finally appear in the finished piece, should be trued up.

At least the working face and working edge are essential to the proper "lay-out" of the piece, whenever measurements are made from an edge.
In laying out a series of measurements, it is important, when possible, that the rule be laid down once for all, and the additions be made on that, rather than that the rule should be moved along for each new member of the series.
In scoring around a board with knife and try-square, the head of the try-square should be held against the working face in scoring both edges, and against the working edge in scoring both faces, and not passed from one surface to another in succession.
In the laying out of a halved joint, Fig.

265, Nos.

15-19, p.