The Shear Characteristic Scale

METHOD

The fabrics used in the book were attached to two bars. The first bar was fixed; the second bar could be moved under tension in a shear direction. The shear measurement was the amount that the fabric would shear before ripples began to appear on the surface of the cloth. The amount was recorded by marker peg holes at 0.5 cm intervals along the sides of the instrument. The amount of recovery can also be measured. The peg holes determined the coding for the book.

Note that low-shear fabrics would not shear to the measure 0.5 cm; therefore, in pattern cutting terms low-shear means virtually no shear.

Percentage

The distance between the bars was 16 cm; each end bar required 2 cm for attachment. This distance can be adjusted to any appropriate length and the percentage shear can be calculated by the following equation.

Amount sheared x 100 e.g. 2 cm x 100 = 12.5%

Original length 16 cm

Drape

Drape is the ability of a fabric to hang in soft folds and to fit around a figure, particularly in movement, without creating angular distorted creases and buckles. The strain is often across the fabric and thus good draping is needed across fabric falling flared shapes. The drape test done for these experiments concentrated on a crossway hanging test as this is a good guide to a fabric’s potential to drape. Drape is a characteristic valued in many fabrics, it is only a part of that elusive quality ‘hand’. ‘ Hand’ is a combination of many qualities which will differ in different fabrics and this I believe is not measurable.

A simple assessment of how fabric may drape vertically can be made by holding vertically a gathered sample piece.

The increased drop which would result from the weight of a larger piece of fabric would have to be taken into account. The difficulty of assessing how fabric may behave in circular cut is demonstrated on page 21. asymmetrical shapes, crossway cutting and the affects of joining different curve shapes would add further complexity. The drape meter test (still recognized by the BSI), which drapes cloth over a circular disk, has scant relationship to the hang of clothing.

The new simple visual test, using a 20 cm sample piece, is only given as a guide across the five categories.