Textile Structure
how cloth is put together
Concept

Twill direction — where it appears

Whether a twill's diagonal runs up to the right or up to the left, which is a property of the draft and not of the yarn. It interacts with the yarn's twist, so the same twill in an S and a Z yarn does not look the same.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

The 2/2 twill both ways round. The same twill stepped one end to the right and one end to the left. Every quantity the matrix can produce is identical for the two, so the direction is real in the cloth and invisible in the arithmetic.

Twill direction, and how it is named

The two twills are mirror images, and every quantity the matrix can produce is identical for both. What separates them is the yarn, which has a handedness of its own — and the angle, which is forty-five degrees only in a square-set cloth.

weaves · Foundation weaves Z twill, Z twist. A square of cloth with two directions on it. The broad lines are the twill, whose angle 45.0° from the warp comes from the setts alone — 24 ends and 24 picks per centimetre. The fine lines are the surface fibres of the warp ends, at 25.3° from the warp because the yarn is twisted 900 turns per metre. Between them is 19.7°, and that is the whole of the rule.

Twist and the twill line

The oldest rule of thumb in weaving says to weave a Z twill from S-twist warp for a bold line and from Z-twist warp for a subdued one. Both halves of it are geometry: the twill's angle comes from the two setts, the fibres' angle comes from the twist factor, and the rule is their difference.

setting · Twist

Named alongside it

The objects these essays reach for when they reach for this one.

Twill angleYarn twistAppearanceDenimHandednessHelix angleLustreSettSpecular reflectionTwist directionTwist factor

All concepts