This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
The section of the window soffit shown at Fig. 9 shows a cast-iron frame, the outer edge of which takes the place of the weather stop, and is ornamented with an egg-and-dart molding. The section of the iron jamb and head shown at a are for either a stationary window set directly in the iron frame or a French sash window, the hinges of which are secured to the iron frame with countersunk tap screws; or, when a wooden hanging stile is introduced, as shown at b, a pivoted sash may be used. The decoration of the weather stop and the inside of the frame should conform to the general design of the building.
The pattern for the body of the frame would be modeled in wood, and the decorated parts done in clay, cast in plaster, and applied to the body of the pattern. The outer and inner faces of the frame should have considerable draft, as shown, so that the casting may be easily withdrawn from the mold. If the requirements of the case demand a transom bar in the frame, its construction should be somewhat as shown at e, Fig. 10. A lug is cast on each side of the frame, and the transom bar is secured to these lugs with countersunk screws. The position of the sash is shown at f, and the transom may be hung directly from the iron frame at the top, or pivoted, as described in Fig. 9.
12. It frequently happens that the window-frame casting includes the outside casing and molded reveal, as in Fig. 10, which shows a richly ornate soffit. In this case the reveal of the soffit a, or the jamb at the side of the opening, is first set, then the frame b is put in place, and last the casing, or architrave, c, the head of which is checked into the stone. The only difference in the modeling and casting of these pieces is that the architrave c has the rosette ornament, while the reveal b has a repeating ornament modeled and cast separately. By this procedure, only one model is required for the rosette, and one for the repeating ornament;
§l2 and castings from these are taken until the required quantity is obtained. Thus, in case of a failure in casting the ornament, the entire casting of the soffit or architrave is not made worthless, as it would be if the ornament was cast with the main detail in one piece and a portion of the ornament proved defective.
13. Door frames may be most elaborate, or plain and simple. As a rule, when cast iron is used for a door frame, it is more properly a jamb and architrave, though in some cases the door frame proper is of iron, the same as a window frame, and the hinge butts are secured directly to it, unless a regular wooden door frame has been provided. The design shown in the illustration, Fig. 11, is the soffit of a simple molded jamb and architrave, the wooden door frame fitted against it. Both the jamb and the architrave are secured to the stonework with expansion bolts, and the joints bolted together with countersunk screw bolts. In designing a door frame, the two chief points to bear in mind are the "draft" and the proper location of the joint between the two pieces. All joints of this character should be specially designed, and so placed that they may form the meeting line between two moldings, as shown at a, so that they may be practically invisible. In very large work, and in buildings that are entirely of iron construction, it is better to set up a series of jamb pieces 2 feet apart, of 2" X 2" angle iron to bolt the door jambs to, the inside ends of which have knees, to which the door frame proper is bolted. The architrave should also have an angle-iron frame set up against the stonework and secured with expansion bolts, and the architrave should be secured to this with countersunk screw bolts.