Quantity of Material in a Piece.—To find the weight of warp and weft of given counts in a piece, the total length of yarn in the piece may be found, and divided by the yards in 1 lb. of the counts of yarn used. This will give the weight in pounds. The following example will make the principle quite clear:—
Example.—Find the weight of warp and weft in a piece woven 30 inches wide in a 70 reed (Stockport) cloth 90 yards long, from 95 yards of warp, 80 picks per inch, the counts of twist or warp being 30’s, and counts of weft 40’s.
If the piece is 90 yards long, the length of warp used will be somewhat in excess of this, as the warp in interlacing with the weft is bent out of a straight line. The amount of “milling up,” as it is called, varies according to the number of intersections in the pattern or weave of the cloth, and with the counts of yarn used. It will also vary considerably according to the elasticity of the yarn. Twofold yarns are more elastic than single, and therefore will require a shorter length of yarn for a given length of cloth.
In this example 95 yards of warp are used to weave a 90-yards piece, an allowance of a little over 5 per cent.
In making the calculation for the weft it is necessary to take the width in the reed, as this length of weft is used every pick. The cloth will contract a little owing to the pull of the threads when woven, and when calculating for a given width of cloth care must be taken to calculate for the reed width and not the cloth width only.
In the present example the width in the reed is given, and so the cloth will be somewhat narrower than this when woven.
TO FIND WEIGHT OF WARP.
840
yards in 1 hank