Jacquard Weaving and Designing

by T. F. Bell

Fig. 51

There is a groove or rebate in the top edge of it for holding the mails, as shown in [Fig. 51] at A and B. Sometimes the grooves are at both sides, as shown at A¹. All the mails required for the harness are put on the one slabstock, which is set directly under the cumber board when the harness is being levelled.

Fig. 52

A levelling frame is better than a slabstock; it is for the same purpose—that of keeping the mails firm and level when being tied to the neck twines. It consists of two flat bars of iron, C, C ([Fig. 52]), which can be bolted together in the form of a frame by the use of two stays, one at each end, and by the same screws be bolted to slotted brackets, A A, B B, fastened to the frame of the loom. Sometimes two hanging brackets, as D, are used, fastened from the top or heddle-bearer of the loom. The levelling bars, C, C, rest in these brackets, and can be fixed firm in them with a pin or cotter. If there is any yield or spring in the brackets, they can be stayed from the front of the loom as well, as the frame should be made very firm. The distance between the two bars should be 4 in. or 4-1/2 in., which will suit any harness; if only narrow harnesses, as 8-row, are required, it may be an inch narrower. The length of the frame must suit the breadth of the loom. It should be perfectly straight and level on the upper edges, and should have two rows of holes bored in it, about 2 in. apart, for pins and skewers to pass through above and below the wires on which the mails are strung, so as to keep them firm.

LEVELLING THE SLABSTOCK OR FRAME

Levelling a harness, or rather levelling the mails of the harness, is the most important part of the mounting, as, if the mails are not levelled as true as a straight-edge, good work need not be expected from the loom. The position in which they are levelled, in relation to the breast beam and back rail, will depend upon the nature of the cloth to be made, to a certain extent; but as a general rule, for ordinary work, the eyes of the mails should be half the depth of the shed required to be drawn below the level of the breast beam for hand loom work, and a little more than that for power-loom work. This is to have the top and bottom portions of the shed of an even tension, and to make both sides of the cloth equally good. The position of the back roll can be altered a little afterwards, if it is required to slacken either the top or bottom portions of the shed. Raising the back roll throws up the weft pattern to the under side of the cloth, and sinking the back roll gives the upper surface of the cloth a finer appearance, by tightening the top portion of the shed. A 3-1/2-in. draw of the harness is sufficient for power-loom work, and perhaps less would sometimes be preferable. Levelling the harness mails 1-3/4 in. for light work, and 2 in. for heavy work, below the breast beam should be a good average standard for a 3-1/2 in. draft of harness. The levelling frame or slabstock is levelled to this height by means of a spirit level and straight-edge, making allowance for whatever spring there may be in the harness after it is tied, and the wires drawn out of the mails. This can only be ascertained by experience, and depends principally on the tension the mounter puts on the twines when tying them; it will also depend upon whether the harness twines have any spring in them or not, but they should be well stretched before being used, to avoid this. A mounter who ties slackly will generally make a more level harness than one who ties tightly. About 1/8 in. may be allowed for the mails to rise if the cords are slackly tied, and if tightly tied 1/4 in. may have to be allowed, and sometimes more than this.