Preparation of flax - line
- in mid 20th century

There are two types of flax spinning:

  • Scutched flax spinning: the raw material is the long flax fibre (or line flax) - spinning of scutched flax and tow can be either dry or wet
  • Tow spinning: the raw material is the short fibre produced during combing or scutching.

Flax is delivered to the spinning mill in the form of bales of line flax. The line flax is stored until required and then undergoes the following operations:

  • Hackling
  • Drafting
  • Spinning

Hackling
Hackling is the word used to describe the combing of fibres in flax processing (in processing other fibres the word combing is used). Hackling is carried out on hackling frames, as opposed to smaller combers used for wool or cotton. Hackling can be either discontinuous or, on more modern hackling frames, continuous. Feeding is done manually, in “hands” of 80 to 120 g, although automation is being developed.

In discontinuous combing, the clamps holding the strands circulate round the machine. In an upward and downward movement, the line flax is presented to a double set of combs. The combing action is vertical, the movement of the combs downward. The frequency is 360 beat-ups/min for the feet and 300 beat-ups/min for the tops. The production of the machine is 60 kg/h
In continuous combing, the clamps are replaced by a conveyor belt circulating round the machine. The movement of the plates supporting the combs is also rotative, but the whole arrangement functions continuously. Production can reach 120 kg/h.


Combing waste, consisting mainly of short fibres (with some shive), is called hackled tow. This is recuperated by doffers and collected in containers located underneath the machines.

After combing, the sliver of line flax is automatically placed on a slanted table consisting of a series of moving transversal or gill bars.

The strands are crossed to form a sliver. This sliver is fed to two calendar rollers and, after coiling, is pressed into packages to be stocked. The weight of the slivers varies between 20 and 40 g/m, depending on the yarn count to be obtained.

Preparation for line yarns
As with wool or cotton spinning, the slivers undergo a series of doubling and drafting operations. The principle of flax drafting is identical to that of other fibres. All the machines used are of the open-gill type.

The machinery or set of drafting frames, i.e. the sequence and number of machines used, can include:
  • a doubling frame, on which the combed slivers are joined to compensate for irregularities in the raw materials, yielding a regular yarn quality (the doublings are 1 to 6)
  • four open-gill drawing frames for four drafting operations. Drafting ratios vary from 8 to 12, depending on the yarn count required
What distinguishes these machines from those used for wool or cotton is that doubling is effected in front of the machine and not behind it, as shown right.
  • one roving frame to draw out the sliver and transform it into a rove. The roving frame also has gills (the draft ratio is 10 to 14)

As a result, each sliver is drafted separately before being doubled. This is necessary because the principal aim of preparation (apart from the progressive reduction of the count of the sliver) is the drawing out of the linen fibre itself. Drawing out is the result of the combined action of the pins of the gills and the pressure exercised between the drafting roller and the wooden delivery roller.