Staple is a term referring to naturally
formed clusters or locks of
throughout a fleece that are held together
by cross fibres. The staple strength of
wool is one of the major determining factors
well as the sale price of greasy wool.
Virtually all fleece and better grade wool
skirtings sold at
are objectively measured prior to the sale
with the average results printed in a catalogue.
Staple strength is calculated as the
force required to break per unit staple
thickness, expressed as
newtons per kilotex or N/tex. Position
of Break (POB) is measured in conjunction
with staple strength and is a measure of
the position in the staple (base, mid or
tip) where it will break given enough force.
Forty or more staples must be measured to
in order to conform to the Australian Standard.
Wools under 30 newtons per kilotex are considered
tender. Currently wools over 40 newtons
per kilotex are preferred and attract a
premium. Seasonal conditions or the health
of the sheep may influence the soundness
(strength) of the wool.
The Australian Standard requires that
sale lot has a minimum of 55 staples measured
with the average calculated and produced.
The variability of this measure is reported
coefficient of variation (CV%). Staple
length generally determines the end use
of wool, that is, whether it will be used
in weaving or knitting. The longer wools
are processed in the worsted system (weaving),
which are called combing types, and are
generally around 51 millimeters (mm) and
longer. Short stapled wools are more profitably
used in the
section where high grade material may be
produced from superfine wool. Staple length
(mm) is highly correlated with mean fibre
length in the top (hauteur).
Although traditionally, staple length
only referred to animal fibres, it is now
used when referring to animal and manufactured
fibres as well.
The opposite term is filament
fibre, which is fibre that comes in continuous
to near continuous lengths for use.
from the cocoon of a silkworm, is called
a silk filament.