Upon commencing the warping of the loom the first matter to be decided is the length of the threads. Some extra length must be measured off besides that actually used for weaving, to allow for what is taken up in fixing the threads and winding them round the rollers, and as it is not convenient to work more than about half-way up the loom, this also has to be allowed for in the length. The threads must all be cut to one size, and since they have to be doubled in halves when placed on the loom, this should be twice the required length.

Another question for early decision is the number of warp-threads that may be allowed per inch. This varies with the coarseness of the strings and the thickness of the weft that will have to pass to and fro between them; what governs both of these points is the design, whether there is much detail or not, for if the drawing is complicated the warp-strings must be fine in order to be able to carry it out; this point will be better understood after some experience of working. Fourteen to sixteen threads to the inch is a very usual number.

The fixing of the threads in the upper roller is a very simple matter. It is done by doubling each in halves and placing the loop thus formed over the metal pin, which for this purpose may be temporarily suspended by string to the frame of the top of the loom just above the roller. It can be dropped into its place in the groove when all the threads are looped upon it, and made secure there for the moment by tying some string round the extremities of the roller.

Each thread is now taken separately through the comb-like instrument. The cross-stave is laid upon this, so it is well to put it in place now, and carry the threads alternately in front and behind it, whilst passing them through the comb. The threading of the strings through the comb decides the number there will be to the inch, so they must be put through at the required distance apart.

The upper roller is next given a complete turn, which will make the metal pin and the threads that are round it secure in the groove. The winding up must be continued until only about three inches of the warp-string hang below the lower roller. Some kind of tension must be applied to the threads whilst this winding is going on, or it will be done irregularly; a hand, or several hands, holding it, answers the purpose well enough.

The next process is to fix the threads securely in the lower roller. The difficulty here lies in getting the placing and tension of the threads between the two rollers exactly regular and even. If some were slack and others tight it would be very awkward to correct afterwards, and impossible to weave upon properly if incorrect.

Fig. 178 shows a practical method by which the warp may be fixed in the lower roller, but any contrivance will do that gains the required result. To carry out the fixing as in the diagram, the roller must be turned so that the groove comes just at the centre in the front. Four lines of warp-thread are then fixed from end to end of the roller, two above and two below the groove. Each warp-string in turn is now threaded in and out of these cross lines, as shown in the diagram. This places them in regular order, at the correct distance apart, and keeps them at very nearly the same tension throughout. The metal pin is now placed in the groove and pushes the threads before it. It must be temporarily made firm there by string tied round the roller at intervals.

The next process is to tie the warp-threads in knots, either two or four together, just where they emerge below the pin. This prevents any giving way, and if the threads are pulled just equally tight immediately before the knotting, the tension of the entire warp will be the same. The lower roller is next turned round until the metal pin is made quite firm in its place by the warp-threads passing across the face of the groove. The warp will now be fixed in the loom as shown in the drawing in fig. 170.

The placing of the coats upon the coat-stave is the next part of the preparatory work. Commence by fixing a line of warp-thread along the exterior side of the coat-stave, making it secure to the bar at both ends. The coats, encircling the stave and a thread of warp, are fixed to this string by a kind of buttonhole stitch (see fig. 179). It is important that each loop should be of exactly the same size; this can be ensured by temporarily fixing a rod across the loom at the point where the loops will encircle the warp-thread, and then taking the loop round this bar as well as round the thread.

To commence making the coats, take a long needleful of warp-thread and secure the end of it to the string at the right-hand end, and then make about three small looped stitches upon it (see needle in progress in the diagram); next, instead of making another of the same stitches, take the thread down below the stave, let it encircle the first thread of the back leaf and then be brought up over the coat-stave and string and be looped under the thread to complete the stitch (see B). Usually a long and a short stitch are taken alternately, but the number of short ones may be varied. This process is continued until all the threads of the back leaf are encircled each by a loop.

A new length of thread must be knotted on to the last one as it gets used up. The weavers' knot, which is shown on p. 291, might be used for the purpose. It would be made use of also if by chance the warp-thread were broken, for it is a knot specially good for the purpose.

When the coats are completed there are still one or two preparations to be made before actually commencing to weave. Either a metal rod or a long narrow piece of wood must now be threaded in and out of the warp-strings and placed in position at the base. This rod can be seen properly placed in position in fig. 179 in front of the lower cylinder. This is put there to keep the lines of the woof horizontal when they are being beaten down by the comb.

Next wind on a bobbin some warp-thread similar to that already on the loom, or, if that happens to be very coarse, let this be a little finer. Now weave two courses with this warp-thread and beat it down with the comb, leaving the woof during the process rather loose. The technique of weaving with all its difficulties is discussed in Chapter XVIII. When two of the warp-thread courses are complete, insert either the pointed end of the bobbin or a blunt needle between the warp-threads below the woven portion, and if necessary move the warp-strings a little to or fro until they are equally separated each from the other all along the line. Next weave about four more courses of the woof; these will serve to keep the arranged warp-threads still more firmly in place. Then with a red pencil rule a horizontal line straight across the warp-strings about one-third of an inch above the woven portion. Wind on another bobbin some wool and weave it to and fro until the space between the woven portion and the red line is filled in. Between each course the comb must beat the woof-threads firmly down. It is often necessary to weave over some portions of the surface more than over others as the threads pack down tighter in some parts. The loom should be now in perfect order for commencing work. The preparatory weaving that has been done is often useful afterwards as a selvedge.

It is necessary to have a coloured drawing of the design for frequent reference whilst the work is in progress; also a tracing of the outline must be marked upon the warp-threads for the worker's further guidance. The tracing upon the threads must be a reflection of the pattern owing to the fact that the work is done from the back. It does not affect the matter if the design is a symmetrical one, but to find the lions of England facing the wrong way in some completed piece of heraldic work would be most annoying. In order to get a tracing of the design upon the threads, a sheet of paper, with a distinct outline of the pattern upon it, must be attached, possibly by pinning, to the further side of the warp-threads, exactly where the weaving is to take place. The outline will be clearly perceivable through the threads, and the next process is to take pen and Indian ink and make a dot upon each warp-thread in sequence round the outline of the pattern. When this is completed, the tracing-paper can be removed, and the dots upon the warp must be taken all round each thread instead of marking one side only. The marking round is done by holding a warp-thread between the finger and thumb, placing the side of the nib against one of the dots, and then twisting the thread to and fro against it. All the marks upon the first thread are treated in succession in this way, then the next thread is taken up and treated in similar fashion, and so on until all are done. Fig. 180 shows a leaf marked upon the warp-threads in readiness for working. This marking should be clear, sharp, and decided, all the lines being taken horizontally round, as in fig. 180; if the pattern seems to run up a thread, a mark just half-way up is sufficient guide. In a piece of work of any size the tracing must be done, a part at a time, for the threads moving slightly when the warp is unwound and the web wound up may displace the marks and make the guiding lines incorrect.