This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
35. A door is a simple piece of paneled work, but the great variety of form and arrangement of its panels, and the enrichment of its moldings, together with the conditions arising from its method of opening or closing, require it to be even more securely framed and glued than a wainscot or other piece of fixed paneled work.
The swinging of a door on its hinges brings a great strain on the joints in the stile on the hinge side, whereas a sliding door hung from the top has its entire weight brought upon the joints of the top rail, or, where hung from the stile, the conditions are the same as with a hinged door.
36. In Fig. 17 (a) is shown a simple four-paneled door which, though devoid of any complicated framing, may be taken as a type of all doors, no matter what may be their specific design.
In laying out a paneled door, a measuring rod is first prepared, in the same manner as for a wainscot. This rod is shown in Fig. 17 (c), where on one side of the line a b, gauged down the middle, is laid off the distance a' c' equal to the width of the bottom rail of the door. Then the distance from the bottom of the door to the top of the middle rail (or lock-rail, as it is called) is laid off at a' e', and from e' is measured down the width of the lock-rail c' d'. Next the whole height of the door is laid off on the rod from a' to b', and from b' is measured down the depth of the top rail b'f.
As the stiles are grooved to receive the panels, a distance of \ inch is laid off from the upper side of the bottom rail at c'f, from the under side of the top rail at f g', and from both sides of the lock-rail at e' h' and d' i'; then we have j' i' as the length of the lower panels and h'g' as the length of the upper panels.
On the bottom rail a' c', we have two tenons k' l' and m'j' each 2 1/2 inches wide, with 1 1/2 inches between them, and also 1 1/2 inches between the lower tenon k'I' and the bottom of the rail. The space between these tenons at l'm' and a' k' is provided with a short projection which passes into the stile to the bottom of the groove. This projection is called a relish, and its purpose is to preserve some solid wood in the groove between the mortises. The double tenons are necessary in the wide rails in order to preserve the strength of the stiles.
On the lock-rail d' e', the width of the tenons is laid off at l'n' and o' h' with a relish preserved at n' o'. The tenon of the top rail is marked at g p', and p' b' is left for the relish; c' d' is then the length of the lower muntin between the shoulders, while c' f is the length of the upper muntin.
On the other side of the rod, at q' s', are laid off the proportions for the division of the widths; thus q' i' and s' w' are each equal to the width of a stile, and exactly midway between these is laid off, at u' v', the width of the muntin, and y' z' is the width of the muntin at the bottom of the grooves to receive the panels. The widths t' x', u' y', v' z', and w'r' are 1/2-inch allowances for the grooves in the stiles and muntins, and at x'y' and z' r' is shown the extreme width of the panels. The mortises and relishes are also here shown as on the other side of the rod.
37. A horizontal section of this door and trim, showing the details of construction, is shown in Fig. 17 (b). At i, i are shown the stiles laid off on the measuring rod at q' t' and w's', and at j is the muntin marked on the measuring rod at u' v'; k, k are the panels inserted in the grooves of the stiles and muntin, which grooves were provided for on the measuring rod at x' t, u' y', z' v', and w' r'.
A vertical section of the door is shown in Fig. 17 (d), where e, e, e are the three rails, grooved as provided for on the measuring rod. The elevation of the door, Fig. 17 (a), shows the tenons of the bottom rail where they enter the mortise of the stile at x x, the tenons of the lock-rail at y, y, and the single tenon on the top rail at w. The dotted lines show the grooves in the stiles, rails, and muntins, and the relishes between and beyond the tenons.
At a, Fig. 18, is shown a perspective view of one of the stiles; at b, b, the ends of the rails; at c, c, the grooves for the panels and relishes; and at d and e, the tenons and relishes.
38. When the measurements for the door are all laid out on the rod, the stiles and rails for all doors of one pattern are cut out of well seasoned stock of proper thickness, and each member is then carefully planed and marked on its jointed edge. The rails are cut to their full lengths including tenons, and the stiles are cut about 4 inches to 6 inches longer than is required; when all the rails and stiles are cut, a set for one door is then taken, and the grooves for the panels are plowed as shown at c, Fig. 18. The mortises and tenons are cut and accurately fitted one at a time, and each is marked for the place for which it is intended. Or, where a number of doors are exactly alike, a half dozen or more rails or stiles of one kind may be taken, placed side by side, clamped tightly and marked for their respective mortises and tenons at one operation. The door now having been made and the tenons carefully fitted to their respective mortises, the door is put together without glue or other fastening, and left until immediately before it is required to be fixed in the building, in order that it may have as long a time as possible to season.
Before being glued, the door is taken apart, the mortises are cleaned, the tenons are spread with glue on their shoulder ends, and after the panels are inserted the whole is driven close with a heavy mallet, laid on a pair of trestles, and secured, until the glue is dry, by means of bench clamps, one of which is placed opposite each rail.
39. In strictly first-class work, the mortises and tenons do not extend entirely through the width of the stile, but are let in from only 2/3 to £ the width, as shown at w, x, and y, Fig. 17 (a). But, in cheaper work and in some "machine-made" doors, the tenons extend entirely through the stile and are wedged up from the outside to render them tight. In such cases, the mortise is made from 1/4 to 1/2 inch larger on the outside than on the inside, and the tenon is then, by means of a couple of wedges, expanded to a dovetail form. Sometimes the wedges are driven above and below the tenons, and are glued in place to make the whole joint tight and secure.