When any of the hooks or needles in a jacquard get bent or broken, they can easily be straightened, or taken out and replaced by others. By putting a thin blade of iron or wood down through the needles alongside of the hook to be replaced, and springing open the passage, the old hook may be drawn out and a new one put into its place. The tail cord must, of course, be cut off the bottom of the hook, and a new one tied on. For changing a needle take off the spring-box and draw up the pin which fastens the row of needles at the back; then the needles in this row may be taken out till the defective one is reached, and the row made up again; or, the old one may be renewed without taking any of the others out. A flat blade is used to slide through the hooks and keep clear the place for the needle to be put in.
_Card Frames._--The cards for jacquard work are usually hung on a frame as O, Fig. 18, wires sufficiently long to catch on both sides of the frame being tied to the lacing of the cards. The number of cards between each wire may vary to suit the space and the quantity of cards. Sixteen to twenty suit very well, the former for small and the latter for larger sets, and for very small sets twelve or fourteen might be more convenient. The frame may be made of round iron rod, or of flat or bar iron, and should be of the shape shown in the sketch, and not semicircular, as is usually the case, which presses the cards together in the centre; almost flat at the bottom, with just enough of a slope to make the cards slide back, is much the best. Of course, for a few cards it does not matter much what shape it is. P (Fig. 18) is the frame for the rollers over which the cards travel to the cylinder. They should be so sloped as to make the cards travel up nicely with sufficient drag on them, and not too much; on this depends a good deal the proper working of the cards, particularly when the machine is running at a high speed, and when springs are not used to steady them on the cylinder. It is usual to have a roller below the cylinder, attached to the frame which holds the cylinder, and the falling cards pass over it. Sometimes the cards, when falling, are shaken, so that some of the wires may not catch on the frame, but pass through it, or the ends of some of the wires may be bent and cause the same result; if the weaver neglects to put these up on the frame before the cards work round to those that have fallen, the wire may catch on it and prevent the cylinder from turning, or, perhaps, pull it out. Sometimes a crank or bend is made in the frame at the outer end, so that the wires can pass up through it without catching. The frame should just be sufficiently wide to enable the cards to pass freely through it with, say, one-eighth of an inch clearance at each side; then, if three or four inches at the outer end is cranked, or set out so as to be a little wider between the two bars than the length of the wires, they will pass up through without catching. Frames of the shape described are, of course, only suitable when the cards are to be wrought forwards--that is, with the cards falling between the cylinder and the machine; but if they require to be wrought both backwards and forwards, as is sometimes the case, the card frame must be made more of a semicircular shape, and the rollers must be set so as to give a sufficient fall to the cards, and keep them firm on the cylinder.