This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
In fretwork, the design is cut out by means of a saw, instead of by the edged tools used in carving. The mode of working has been made pretty evident in describing the tools. In sawing, care must be taken to give short gentle strokes adapted to the thinness and lightness of the wood dealt with.
One of the most general forms in which fretwork is applied is for forming an ornament called a "gallery," used for the tops of cabinets and other articles of furniture. These galleries vary in size according to the nature of the work for which they are intended. They are generally about 1 1/4 in. to 2 in. wide, and their length is 1/4 in. to 3/8 in. less than that of the top upon which they are placed. When getting out the wood, be particular to select as straight-grained a piece as possible; this is indispensable for all kinds of fretwork. Its thickness should be 3/8 in. or 1/2 in.; for miniature work, 1/4 in. is sufficient. Before cutting out, consider the kind of gallery you are to have, and the manner in which it is to be finished at the ends, various modifications being adopted. In some, the ends are tenoned into a turned ornament, having a pin fitting into the top. In others, ends are also made at right angles to the back and tenoned into the ornaments. Where it is necessary to have ends, dispense with the turning, and secure them to the back by means of dovetails. It is necessary to have ends where the top is rather wide, and it is better, wherever possible, and where there is sufficient space, to admit one about 3 in. and upwards long.
Having considered the kind of gallery, the length it is to be, and the manner of finishing the ends, plane it over, take to a width, and square it. You may with advantage get one piece out long enough to make both ends. You should now mark the gallery and ends. It will be necessary not to allow the fret-cutting to come quite to the ends. Whether it is to bo tenoned or dovetailed, you will require sufficient for working; 1/2 in. or 5/8 in. should be marked and left plain for this purpose. The bottom must, of course, always be so, because of fitting, and the top is better straight or plain, whether the design is geometrical or otherwise, as a straight or plain top bar protects to a great extent the other fretwork, rendering it less liable to accident, especially if a scrollwork pattern. The bars should be about 3/16 in. wide, and care should be taken that the cutting is of such a nature as to allow sufficient support to the various parts of the figure, preserving a light appearance with the requisite strength. Galleries are fixed on by means of dowels. When turned ornaments are employed, the pins are usually sufficient, with one dowel or so, to secure it.
In other cases, small dowels are placed at a distance of 3 1/2 in. or 4 in. apart in the back, and a little closer in the ends; one or two dowels in the ends acting as a great support to the back. When marking their position, be careful to select the strongest part of the fretwork, that is, the portion connected with the bottom rail, and where you can bore deepest for the dowels. In boring, do it slowly and in the centre; glue and knock in the dowels gently. It is best to cut them in lengths first, and in pressing them into the holes made to receive them in the top, keep the gallery as upright as possible, and allow all the dowels in back and ends to enter together. Do not get one end in first, or the back ones in and not the ends, or you will be likely to break some of them.
It is sometimes required to place a gallery upon a shaped surface, with which it is necessary for it to correspond. It is then got out of thinner material, about half the thickness of that previously given, to enable it to be bent the requisite shape. The method differs from the preceding one, dowels being insufficient to hold it when bent. After the position it is to be in is determined, the thickness of the fretwork is marked bare, and a groove to receive it is cut upon the work. This should be about 1/4 in. deep and of a uniform depth throughout. The work is carefully bent to this and inserted, afterwards removed and glued. When getting out work of this description, be careful to allow additional width for the bottom bar or rail, so that it will show equal with the top after insertion; that is, add the depth the groove is to be to the width of the bars.
Another application of fretwork is for "stretchers," used principally for the various kinds of tables, and sometimes for other things, both for structural and ornamental purposes. Figs. 723, 724, 725, and 726 are drawings representing forms of stretchers.
In Figs. 723 and 724 the geometrical designs are intended to be used as shown. This is a form adopted for tables in place of the turned one connecting the front and back legs with a cross one at right angles between. The rails are used diagonally, being tenoned into the alternate legs, and passing through an ornament in the centre. You must allow for the diameter of this when setting out, also a space each side equivalent to that against the legs where tenoned. You will be able to put one rail in in one length, but the other will require to be in two halves, on account of the mortices intersecting in the centre of the ornament. The width of these rails will vary from about 1 1/4 in. to 2 1/2 in., according to the size of the work; in some of the largest octagon tables this is sometimes exceeded. The material is usually 1 in. thick; in small work 3/4 in. is sufficient. The top edges may be moulded. In stretchers of this description the top and bottom bars of the rails should be always left strong. Fig. 725 is a very good form if used flatways, intended for a large table, being tenoned into legs at a b and c d.
The whole of the wood for this is not, as might be imagined, got out in one, for the obvious reason that the end pieces connecting a c and b d would be crossways of the grain of the wood and consequently of little use. The stretcher is fret-cut first, the ends being cut separately and afterwards connected. Fig. 726 is a portion of a stretcher where the end is tenoned into a leg and the other into a centre placed rather higher, the edges being either plain-shaped or moulded. It is sometimes required to have the centre of a stretcher cut with a more elaborate design than the remainder. The thickness of wood required for the general part of the stretcher would not admit, or at least not readily, this kind of work to be executed. The centre may then be got out of thinner material, 1/4 in. or | in., and fitted accurately as a panel to the framing of the stretcher. By adopting this plan, the finest description of work may be employed without affecting the requisite strength.