How cotton thread is made: from bud to spool - part 1

Thread is such an essential part of any make. We spend so much time choosing our fabric and design, but it is just as important to ensure that the thread we choose if high quality and perfectly suited to the project. A deeper understanding of thread can help us with this.

But where does thread come from and how is it made? This week we begin a two part look at the manufacture of cotton threads including growing, harvesting, ginning, carding and drawing and spinning.

Growing the cotton for thread

Cotton is a soft, stable fibre that grows in a form known as a boll around the seeds of a cotton plant. Each fibre is a single elongated cell that is flat twisted and ribbon-like with a wide inner hollow called a lumen. The cotton fibres are attached to the seeds inside the boll. There are usually six or seven seeds in a boll and up to 20,000 fibres attached to each seed.


Harvesting the Cotton

As recently as 1965, over a quarter of cotton was harvested by hand. Today harvesting is highly mechanized. Harvesting machines called strippers and pickers efficiently remove the cotton while leaving the plants undisturbed. From the pickers, the cotton is formed into bales. Cotton is classed of the basis of samples cut from these bales. Cotton is classed on its cleanliness, degree of whiteness, length of fibre and fibre strength.


Ginning Cotton

From the field, seed cotton moves to nearby gins for separation of lint and seed. The cotton first goes through dryers to reduce moisture content and then through cleaning equipment to remove foreign matter. The cotton is then air conveyed to gin stands where revolving circular saws pull the lint through closely spaced ribs that prevent the seed from passing through. The lint is removed from the saw teeth by air blasts or rotating brushes and then compressed into bales.


Carding and Drawing

Next up is carding. Carding is process similar to combing and brushing. The operation is performed on cotton, wool, waste silk, and synthetic fibres by a carding machine that consists of a moving conveyor belt with fine wire brushes and a revolving cylinder, also with fine wire hooks or brushes. The belt and cylinder pull the fibres to form a thin web. The web is fed into a funnel-like tube that forms into a rope-like body about ¾ inch in diameter. This is called a sliver. After carding several slivers are combined into one strand that is drawn to be longer and thinner. The drawing operations produce a product called roving which has fewer irregularities that the original sliver.


Spinning Cotton

Spinning is the process that turns the cotton into yarn. The twist is important in providing sufficient strength because twisting causes the filaments to interlock further to one another. Cotton spinning is an ancient art. For thousands of years, fibre was spun by hand using simple tools, the spindle and distaff. For any fibre, yarns with a smaller amount of twist produce fabrics with a softer surface; hard-twisted yarns, provide a fabric with more a more wear resistant surface.

Continue to part 2
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