This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
Cote Grading Machine is called by the inventor "the Improved Pantograph," and is an improvement that enables patterns to be produced which have not the defect of a proportional width-grading to the length, that would be produced by the ordinary pantograph. It is a simple machine to operate, and in its latest form it will produce correct shapes of patterns. The machine is illustrated in Fig. 75, and it will be observed to consist of a cast-iron frame, containing in the base a sheet of plate-glass. The handles A, A are arranged so that it will raise the bars B, B, in which slide the movable bars C, C. When this is raised, it allows the paper or board to be placed in position for cutting, and, when lowered, the bars hold the paper firmly to the glass, preventing any sliding. The graduated arms A, B, C (Fig. 76) are used to regulate the length of the patterns, and in use require to be adjusted to the same figure on each arm. The width is regulated by the nut D, which slides along the scale either side of zero. Above the handle in Fig. 75 is a grooved wheel that is free to turn on its centre. It is situated over the hole J in Fier. 76, and when the little revolving knife is placed in J, a pattern - the same size as the one used for a standard - is cut out. One hole above, i.e. K, gives one size larger, and a hole below, i.e. I, a size smaller.
Fig. 75. Cote Grinding Machine.
Fig. 76. Plan Of Cote Grading Machine.
To use the machine for cutting sole-shapes in sizes, measure the length of the standard-shape by the rule * provided. Supposing it is size 7's men's, it would measure 32. The machine is set to 32 at A, B, and C (Fig. 76), and will enable it to produce patterns differing in length by sizes, i.e. 1/3 in. The unit of grade-width is now to be decided - for sake of illustration, say 1/2 between tread and tread per size. The total width of the tread is measured, say 3 ins., this would measure thirty-six one-twelfths of an inch. Subtract the length from the width, thus Length ... ... 36 units.
Width ... ... 32 „
Difference ... ... 4 „
The screw D is moved to the left hand of zero four units, and the machine is adjusted ready for use. When the length exceeds the width, the screw D is put to the left; and when the width exceeds the length, the screw is placed to the right hand of zero.
Last Sections, or breech patterns, are sometimes made so that a particular idea may be produced. They must be accurately cut, and, if made for several sizes, should be correctly graded or scaled. In Fig. 77 a longitudinal breech pattern is illustrated, and is so cut that it will allow a last to pass through it lengthways, just touching it equally all round. This would ensure a correct pitch and spring being obtained, and if the positions of measuring the joints and insteps of the last were marked, it would enable the girths to be taken in the correct positions. Fig. 78 illustrates a cross section, or breech, taken at the joints.
* This is a rule divided into one-thirds of an inch, and numbered from the end consecutively without a break. It is sub-divided into oue-tenths.
The insole shapes, if they are prepared for last-making, must be accurately graded, so as to preserve the initial shape, and yet be adapted to the measurements required by trade custom. This is illustrated by Fig. 79.
The Woods used for Last-Making in England are principally beech and charme. Beech in nature and quality depends a great deal upon the soil where it is grown, and upon the rapidity of its development. The trunks of small trees, or the branches of the larger ones are chiefly used for last-making. The thickness of the bark is, as a rule, a guide as to the quality of the wood - the thicker the bark the better the timber.
Charme, or French wood, is imported into this country in blocks, roughly shaped. They are thus called chopped blocks. The wood is of the hornbeam family, and is close in the grain, hard, and usually very free from knots.
In selecting a suitable wood, the chief points to be observed in making a choice are: a clean cutting wood free from knots, non-liability to split, hardness of texture, smooth grained, and not hygroscopic.