A High School Course in Wood Pattern Making (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 edition. Excerpt: ...is allowed to lie flat on the bench in a damp atmosphere, the exposed side will absorb moisture from the atmosphere and swell while the under side is protected and remains the same size, causing it to curl concave down. (Fig. 25.) Fig. 24 Fig. 25 The old wood at the heart of the tree will dry out less quickly than the newer open grain sap wood near the bark; so a board has a tendency to curl away from the heart. (Fig. 26.) For this reason, a pattern maker, in making a job which is very particular, would select a board which is sawed radially with the log, or a quarter sawed board. To determine a quarter sawed board, one must inspect the annual rings on the end of the board. (Fig. 27.) P/a/t? Sawed Sowec/. Fig. 27 The porous, end grain of a board dries and contracts more quickly than the solid mass of wood, causing a strain and finally a split. This is called a check and may be prevented by shellacing the end, immediately after it is trimmed off. The unit of board measure is the board foot. Drawings Drawings are representations of the finished iron object. They are made for the machine shop, to guide the machinist in cutting, boring, planing and fitting, so as to produce an object embodying the general requirements. No drawing of the pattern is furnished for the pattern maker. The pattern maker gets what information he can from the machine shop drawing and then makes, from his imagination, some form in wood, which the workman following him can use to produce the required object. The pattern often does not look like the desired object, but bears only a general resemblance to it. Drawings are seldom made full size. The pattern maker lays down a full size drawing of the pattern on a board, making the lines with a knife instead of pencil. Drawings are...