Textiles, for Commercial, Industrial, and Domestic Arts Schools / Also Adapted to Those Engaged in Wholesale and Retail Dry Goods, Wool, Cotton, and Dressmaker's Trades

by William H. Dooley

Experiment 31—Determining the Size of Yarn

Apparatus: Yard stick.
Materials: Sample of cotton, woolen, and worsted yarns.
References: Textiles, pages [49], [51], [52].

As yarns used in the manufacture of fabrics are of all degrees of thickness, it became necessary to adopt some method of measuring this thickness. For this purpose yarns are numbered, so that when the number is known an idea of the size of the yarn may be gained. It would seem advisable to number yarns of all kinds according to one fixed standard, yet unfortunately this is not done. The methods of counting yarns are many and varied. The usual method is to estimate the yarn number by taking the number of hands of a definite length which make up some given weight. Thus in the worsted yarn, No. 1 is a yarn that has 560 yards to a pound. No. 2 worsted yarn has two times 560 yards to a pound. How many yards in No. 12 worsted yarn? How many yards in No. 20 cotton yarn?

Experiment 32—Test for Twist in Yarn

Apparatus: Test dial.
Material: Piece of yarn.
References: Textiles, pages [131-132].

As the amount of twist in yarn determines its strength, it is necessary to know the amount of twist per inch in given yarn. The strength increases up to a certain limit. When this limit is reached, increased twist does not make the thread any stronger. We may also have twist and strength at the expense of bulk. The test consists in finding out the number of turns per inch, and this is done by an arrangement where a certain length of yarn is stretched between two points on a twisting machine and the twist taken out. The number of turns required to take the twist completely out are registered on a dial at the side of the apparatus.

Poor cotton that goes into coarse goods cannot be spun as fine as the finer cotton. The shorter the cotton the more twist is required to spin it, and the more twist that is put into the yarn, the less will be the yardage. Whereas on the finer and longer cotton there will be less twist put into it, and the yarn will be much stronger. Find the twist in different kinds of yarn.

Experiment 33—Determining the Direction of Warp and Filling

Apparatus: Microscope.
Materials: Silk, cotton, and woolen fabrics.
Reference: Textiles, page [238].

When one examines a fabric the first thing to do is to determine the direction of the warp and direction of the filling.