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Introduction Thread Numbering Other Points

Thread Numbering

Numbering Systems

Threads used in lacemaking are usually made up of several single strands twisted or plied together. The numbering system for threads has two parts: one related to the thickness of the single strand and the other to the number of strands (ply). Whereas the ply is expressed in a straightforward manner, the thickness of the single strand is not specified directly but as a ‘count’ related to the length per unit weight.

Thus, a 30/2 thread (Nel) is a two-ply thread, and each single strand measures 30 x 300 yd / lb. Note that the ‘count’ is inversely related to the thickness — the higher the count, the thinner the thread. So a 30/2 thread is thinner than a 20/2 thread. (Obviously, for a thread of a particular count, the thickness will be directly proportional to the ply — the higher the ply, the thicker the thread. So a 35/3 thread is thicker than a 35/2 thread.)

Comparing threads for changing patterns

The key point in comparing threads for changing patterns is that the thickness of the thread is its diameter. When reducing or enlarging a pattern, the diameter of the thread should be changed by the same amount so as to keep the ratio between the diameter and the size of the pattern constant.

Measuring the ratio of thicknesses

The most obvious way of comparing the thickness of two threads is by measuring their diameters. It is easiest to do this by winding the thread round a ruler and measuring the number of windings over a certain length. To obtain the diameter divide this length by the number of windings.

Consider as an example that we wish to change from a 80/2 thread to a 35/2 thread. When we wind these round a ruler we find that for the 80/2 thread there are 30 windings per cm, whereas for the 35/2 thread there are 20 windings per cm (shown on the right). Thus, the 80/2 thread is thinner than the 35/2 thread by a factor of 20/30, i.e. it is 67% as thick. (Conversely, the 35/2 thread is 150% the thickness of the 80/2 thread).

Although the method is not exact because one person may wind more tightly or loosely than another, if the same person makes both windings the result will be accurate enough in practice.

Calculating the ratio of thicknesses for the Table

Instead of measuring the ratio of thicknesses of two threads, this can easily be calculated if they belong to the same numbering system. The diagram below may help you to follow the calculation. It shows how the cross-section area of a thread changes with thread number and ply.

You will see that it is easy to find the relative difference in cross-section area of two threads but, as we want to compare the thicknesses, it is the relative difference in diameter of the threads that we need. It may be obvious to some readers that this will be the square root of the ratios of ply/count for the two threads. However others may wish to check the logic of this below.

As an example, the percentage change in going from a 78/3 to a 35/2 thread is calculated:

This is the value that you will find in the table.

Further information about threads and numbering systems