Before dealing with the doors themselves it will be advisable to acquire a thorough understanding of the frames or cases which are designed to contain them. These frames, being generally built up in reveals formed in the brickwork as the work proceeds, have to be no less than 4 1/2 inches wide - the width or half the length of an ordinary brick - and 3 or 4 inches deep, according to requirements and the depths of the jambs. The frame usually projects about 1 1/2 inches beyond the face or "sight size" of the opening (6g. 596).
The frames are made up of two jambs (or legs), as the posts are called, and a flat or arched head, according to the nature of the opening (Fig. 597), both jambs and head being, of course, of the same size. The jambs are tenoned into the head and wedged, the head generally being 3 inches longer beyond each side of the jambs. These projections are called horns, and are intended to be built into the walls.
Fig. 598 represents a frame for a square-headed door, the jambs of which are tenoned into the head.
Fig. 597. 1/4 Scale.
Fig. 599 shows the head cut out for a segmental-headed door, the joints at the top being similar to. the last, and the head being cut out of a deeper piece of stuff.
Fig. 598. 1 Scale.
Fig. 599. 1 Scale.
Fig. 600 represents a frame for a semi-circular-headed door, the joints at the springing being as shown, and the key being formed on the top of the jamb, and let into a mortise in the circular head and wedged up tightly. The joint at the crown is made similar to Fig. 556, and sometimes also that at the springing, exactly as shown in that Fig.ure (vide Chapter XVI (Joints And Mouldings In Joinery. Joinery Defined).).
Door frames are secured at the foot of the jambs by dowels let into the jambs and steps, as in Fig. 601; or in best work, where the bottoms are apt to rot away from the damp that rises, they are dowelled into projecting stones worked to the same section as the frame (Fig. 602), and painted, so that the difference cannot be noticed at first sight. These are sometimes called cotch stones.
Another method is to let the bottom of the jambs into cast-iron shoes - also of the same section as the frames - which are secured to the stone sills.
The frames, when built as the work proceeds, are often tied in with wrought-iron ties, two or three in each height, one end turned into the wall, and the other secured to the back of the frame (as Fig. 603).
In sections the frames, of course, vary according to the requirements and nature of the work; but all are rebated for the door.
Fig. 604 is a section of a rebated and chamfered frame. Fig. 605, that of a rebated and moulded frame.
Fig. 606, a rebated and beaded frame.
The rear faces, abutting against the brick or stone rebates, are often grooved for the plastering or linings, in addition to the other labour named above (Fig. 607).
Fig. 608 represents the plan of the jamb of a frame with door linings and finishings in an ordinary 9-inch reveal.
Often, to break the joint in best work, the side of the rebate and the door are beaded, as in Fig. 609, or the arris of each is taken off and forms a V joint, as in Fig. 610.
The section of the head is similar to Fig. 611, with the addition of the elevation of the return of the linings, etc, as seen down the jamb.
In very wide walls, in first-class houses, the linings are panelled, as Fig. 612, which represents a section through the head. The jamb would be the same, without the elevation lines shown on.
N.B. - Students - when drawing plans and sections of moulded and panelled work, which returns' and is seen in elevation, between or in front of the parts which are in section - should take care to show all these lines in elevation, that being the correct way, and, in addition, they embellish their drawings. This particularly applies to panelled work.
Fig. 611. 1 1/2Scale.
Small scale elevations of the whole height of these jambs are given on Figs. 613 and 614, the former being the plan and the latter the panelled linings, the rails of which should always correspond and be in true line with the panels of the door - i.e., a door three panels high should have linings three panels high, each panel being of the same height as those on the door, to correspond.
Fig.612. Section 1 1/2" Scale.
Fig. 613. 1/2" Scale.
Fig. 614. Hook Hoo Elevation.
Fig. 615. 1" Scale.
In agricultural buildings door frames are seldom used, the doors being hung at top and bottom by wrought-iron band-hinges, on to hooks which are secured to stones built in the jambs. Fig. 615 is a small elevation, and Fig. 616 enlarged plans and sections, with details of the hooks, etc.
The hooks, otherwise called crooks, are usually used in pairs, and sometimes the top crook (or hook) is reversed, so that the pin of each points towards the other, to prevent the door being lifted off them, in which case the door has to be put in position before the upper band-hinge is attached, or bolted to the framing of the door.
Another method to prevent the door being lifted off its hinges, when hung externally, is to screw the end of the pin of the crook, and put on a nut, which should be permanently fixed.
When very large doors or gates are a necessity, it is very much better to screw the hinge to the lower edge of the bottom rail of the door with a conical pointed projection on the underside, instead of the knuckle to go over the pin; and this cone is made to work in a gun-metal socket, which is leaded into a special stone, fixed a small distance above the level of the threshold or top step immediately under the door, so that the door may swing or spin (as it were) on this cone. In this case it is always advisable to strengthen the band, supporting the door, by means of lugs or ears welded on either side, so that the thickness of the door is grasped by them. They should be at least nine inches high and every eighteen inches along the band-hinge, with a minimum of three pairs. It is needless to say these lugs should be bolted together through the door, and the face of them should be flush with framing; otherwise they will form a ledge or cup for the wet, and cause the bottom of the door to rot.
The knuckle and pin of the upper hinge must be perfectly perpendicular over the centre of the cone to render proper and easy working without undue pressure on particular parts; and the hanging style should be much wider than usual, so that it will have more strength to keep the door from sagging towards the closing or meeting styles.
If this principle of "centre hanging" or "on points" were more extensively used we should have less sagging of doors to contend with, especially with regard to the best doors, and even window shutters in first-class work, for the principle can be applied to the top and bottom of framings, similarly to "door springs," to great advantage.
Before leaving the subject of door frames mention must be made of the practice of using straight door frame heads in arched openings, and nailing a thin turning piece or arch piece on to the top of the frame, so as to fill up the space above to the outline of the arch, as Fig. 617.