This class includes a great variety of forms of iron sash bars, such as those in Figs. 136 to 138; Beading Iron, for ornamental work, as in Figs. 139 to 141; Cross Iron (Fig. 142), for struts; Quadrant Iron (Fig. 143), for building up parts of structures; and other sections useful for different purposes.
Before ordering iron, joists, or iron of the various other sections, it is well to ascertain the dimensions of the usual sections kept in stock by the merchants, or for which the works have rolls. Iron merchants give their customers printed lists of all such sections, and selections should be made from them. If sections of unusual form and dimensions are called for, extra expense and delay are occasioned.
The lists include almost every variety that can possibly be required; for example, in those of Messrs. Boiling and Lowe.
Angle irons are shown from 1/2 inch x 1/2 inch x 1/8 inch thick up to 8 inches x 8 inch x 3/4 inch thick.
irons from 7/16 inch table x 3/4 inch stem x 1/8 inch thick, up to 12 inch table x 3 1/2 inch stem x 7/8 inch thick.
irons from 5/8 inch wide x 3/8 high x 3/16 thick, to 12 inches wide x 4 inches high x 1/2 inch thick.
iron from 23/4 inches high x 1 inch wide x 1/4 inch thick, to 20 inches high x 111/2 inches wide xl1/4 inch thick.
Plate Iron is made in thicknesses between 1/8 inch and 1 inch.
The different thicknesses vary 1/16th inch each in succession.
Large or heavy plates are more expensive because they require more care and labour in manufacture.
The extras charged upon plates vary slightly in the different districts, as will be seen by the list of extras.
Thus, in Staffordshire, an extra is charged if the plate is more than 15 feet long or 4 feet wide, or if it contains more than 30 square feet surface, or weighs more than 4 cwt In the North of England many of these extras are given up, and a proportion (say 10 per cent) of an order for plates, weighing as much even as 10 cwts. per plate, will be rolled without extra charge.
Plates less than 1/4 inch thick are charged extra in the Cleveland district.
Common plates are used for shipbuilding, and called " ship plates."
Best best plates, for the better class of shipbuilding, such as men-of-war, also for boilers of engines.
Treble best plates are used in boilers of superior construction, and first-class work generally.
Charcoal Plate is produced by a peculiar process of refining with charcoal instead of coke.
It is very tough and strong, and can be bent either way, with or against the grain, and is used chiefly for the manufacture of utensils which are stamped out of it.
Tin Plates are coke or charcoal iron plates coated with tin.