by katie  May 30, 2018  Blog, Technical Weave
Once you have decided on a project you may want to work out how much yarn you are going to need. This may be so you can buy or dye the correct amount without vastly over or under estimating.
The following will take you through the calculation to do this. It looks like a lot but they should be relatively straight forward things to work out. For the sake of simplicity I will work in centimetres/meters but the same can be applied to inches/yards.
The calculaion is as follows:
Total number of ends x total length of warp (m) = amount of yarn needed (m)
How to work out the total number of ends
 EPC (see calculating sett) x (width of woven piece (cm) + shrinkage/takeup (cm)) = Total number of ends
 The shrinkage/takeup is usually assumed to be 10% of the width of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.
How to work out the total length of the warp
 Length of woven piece(s) (m)+ shrinkage/takeup (m) + yarn wastage (m) = Total length of warp (m)
 If weaving more than one piece add the lengths together
 The shrinkage/takeup is usually assumed to be 10% of the length of the woven piece but this can vary by a large amount depending on the yarn, structure and finishing. Sampling will give you a more accurate number.
 Yarn wastage is the amount of yarn used to tie on to the front beam plus the warp woven for even end distribution plus the loom waste (the amount of yarn left on the loom not able to be woven).
 It is often easier to work out the calculations in cm and then convert to m by dividing by 100 at the end.
As a working example:
Total number of ends:
 8 EPC
 50cm wide warp
 10% of 50cm = 5cm shrinkage/takeup
8 x (50 + 5) = 440 ends
Total length of warp:
 Three 50cm woven pieces = 150cm
 10% of 150 = 15cm shinkage/takeup
 10cm to tie on
 5cm to weave distributing picks
 50cm left on the loom that cant be woven
150 + 15 + 10 + 5 + 50 = 228cm (2.28m)
440 x 2.28 = 1003.2m of yarn needed for the warp
Calculating the sett
by katie  Apr 26, 2018  Blog, Technical Weave
What is a sett?
Once you have chosen a yarn(s) to use use for a warp you need to consider the sett. In other words, the number of warp ends you will want to have in your woven cloth per centimetre/inch (ends per centimetre (EPC) or ends per inch (EPI)).
Things that may affect the sett
There are a number of factors that need to be taken in to consideration and may affect the sett you choose:
Weave structure
A weave structure with fewer weft intersections with the warp will require a higher sett. For example a 3/1 twill will require a higher sett than a plain weave.
Final use/aesthetics of the fabric
If the final outcome is to be a lightweight scarf then the sett may need to reduced considerably. On the other hand if the fabric is to be cut and sewn a much higher sett is needed so it holds together well. A higher sett will also make it harder wearing.
Personal preference
Some weavers prefer to use a slightly higher/lower EPC/EPI and may also beat down their weft harder/more softly.
Bearing this in mind the below is only a guide and other factors will affect the sett.
How to work out the sett
To work this out you need to take your yarn and wrap it around a ruler. Do this with no gaps between but ensure the yarn does not bunch up or overlap. Wrap it around in a 1 cm or 1″ section as shown below.
Dividing the number of times the yarn was wrapped by 2 gives you the EPC/EPI of your woven cloth.
This method is usually a good indicator of the number of ends you will need for a balanced plain weave structure. When we talk about a balanced plain weave we mean a plain weave where the warp and weft are equally visible, neither one dominates the other.
For a balanced twill you would use 2/3 of the number of ends round the ruler.
In the photo above the yarn was wrapped around the ruler 14 times within 1cm. This means I would want to start with 7 EPC for a plain weave or 10 EPC for a twill.
If different structures are to be woven then the EPC/EPI will need to be adjusted. There is a formula to work this out mathematically which can be confusing. It may also be affected by previously mentioned variables which cannot be taken into consideration with a formula. The formula is as follows:
S= T X R
bn(I + R)
S is the sett.
T is the number of times the yarn was wrapped around a ruler.
R is how many ends there are in one repeat.
I is the number of weft intersections in one repeat.
I personally prefer to use the first method mentioned and adjust it taking all other aspects of the woven piece in to consideration. Sampling really is the only way to get just the right sett.
by katie  Apr 8, 2018  Blog, Technical Weave
Yarn is made from a variety of different fibres and it is important to have an understanding of where these fibres come from. The following table show some of the most common types and their origin:
Fibre type 
Yarn 
Origin 
Natural (cellulose)

Cotton 
White boll which surrounds the seed of the cotton plant 
Flax/linen 
Filament fibre from flax plants 
Hemp 
Hemp plant (a Angiosperm phylum) 
Jute 
Corchorus olitorius plant 
Ramie 
Bark of Boehmeria nivea 
Sisal 
Leaf of the Agave sisalana plant 
Bamboo 
Stem of the bamboo plant 
Paper 
Wood pulp 
Abaca 
Leaf of the banana plant 
Banana 
Stem of the banana plant 
Pineapple 
Leaf of pineapple plant 
Coir 
Husk of the coconut fruit 
Lyocel (tencel) 
Wood pulp 
Seacell 
Wood pulp and seaweed (algae) 
Natural (protein)

Sheep wool 
Sheep hair 
Alpaca 
Alpaca hair 
Cashmere 
Cashmere goat 
Mohair 
Angora goat 
Angora rabbit 
Angora rabbit 
Camel 
Camel hair 
Horse 
Horse hair 
Lama 
Lama hair 
Mulberry Silk 
Silkworm cocoons 
Tussah silk 
Tussah silk moth cocoon 
Synthetic

Vicsose 
Wood pulp 
Rayon 
Cellulose from a variety of plants 
Polyester 
Synthetic resin 
Elastane 
Minimum of 85% polyurethane polymer 
Acrylic 
Minimum of 85% acrylonitrile monomer 
Some fibres come from a natural source but are classed as synthetic. This is due to the manufacturing process the fibre has gone through to and whether the end fibre is biodegradable.
by katie  Mar 31, 2018  Blog, Technical Weave
What is twist and ply?
When choosing a yarn it is important to consider the twist and ply as this affects how the yarn behaves.
Twisting yarn is the process of wrapping together (in a spiral motion) fibres to make a singles yarn and then singles to make a plied yarn. Twisting fibres together, such as when spinning, gives the fibres the strength to be woven in to cloth. Twisting these singles together to make a plied yarn adds even more strength.
The ply of a yarn is the number of singles that have been twisted together to make up a yarn. A single yarn would have a ply of one.
We describe the twist of a yarn as either an ‘S’ or ‘Z’ twist. To determine which way a yarn is twisted, hold the yarn vertically and visualise the diagonal in each of these letters. If the fibres appear
to be going in the same direction as the diagonal in an ‘S’ then it is an ‘S’ twist yarn. If they are going in the opposite direction then it is a ‘Z’ twist yarn.
Why is it important?
When yarn has been plied together the single strands are often ‘Z’ twist yarns which are then plied in an ‘S’ direction. If multiple ply ‘S’ twist yarns are then to be plied together, such as in a cord, they would be twisted in a ‘Z’ direction. Alternating twists in this way gives the yarn stability and strength.
If a yarn is plied together using the same direction twist as the single strands, for example the single strands were twisted in a ‘Z’ direction and the yarn was also plied in the ‘Z’ direction the resulting yarn will have a tendency to curl. This is apparent in fabrics such as voile.
The number of twists per meter is also important. This information is not always given with the yarn as standard but it will be displayed a TMI (twists per metre or TPI twists per inch). Some yarns are highly twisted and have lots of twists per meter while others are more softly twisted with less twists per meter. Shorter staple fibres will need a higher twist than longer staple fibres to give them the strength needed to be woven.
As a yarn’s TPM increases as does it’s strength until it reaches it ‘optimum twist’ (different for every yarn). Optimum twist is when the yarn is at its strongest. If twisted more than this it starts to weaken. weakening the yarn in this way is sometimes necessary to create a desired effect.
How twist and ply is applied
The twist of a singles/yarn defines the characteristics of the yarn:
Low twist yarns 
High twist yarns 
Softer (produce softer, lighter fabrics) 
Smoother, harder and stronger (produce finer, crisper fabrics) 
Absorbent 
Can be water repellent 
Less hard wearing 
More resistant to abrasion and pilling 
Fabric more relaxed and less likely to curl 
Very high twist yarns are lively and the fabric more likely to curl 
It is very important to consider the twist of a yarn when weaving a fabric as this may help us us achieve a desired fabric. These are a few examples of some fabrics in which the twist is very important:
Fabric 
Twist characteristics 
Crepe 
Very highly twisted yarn 
Voile 
Fibre spun in ‘Z’ direction with yarn also spun in ‘Z’ direction. High twist yarn which likes to curl but also creates transparency. 
Poplin 
Yarn which has been spun in an ‘S’ twist using two singles spun in ‘Z’ twists. 
Herringbone structured fabric 
When the yarn twist and direction of the twill structure are in opposite directions the twill will be more prominent e.g. ‘S’ twist yarn with ‘Z’ direction twill 
Sewing thread is made up of three ‘S’ twist singles then plied in a ‘Z’ direction which creates a tear resistant yarn.
Yarn Counts
by katie  Mar 23, 2018  Blog, Technical Weave
What are yarn counts
Yarn counts can be a confusing topic but it is a useful piece of information.
The yarn count tells us the thickness and ply of the yarn. All yarn has a yarn count although this is not so obvious in some yarns such as knitting yarn which are often described in words e.g. double knit etc.
Counts are expressed as two numbers separated by a forward slash followed by the count system abbreviation e.g. 16/2 nm, 2/16wc etc. One number is the count, this tells us the length of yarn for a given weight of each individual strand of yarn. The other (usually smaller number) tells us how many strands of yarn have been plied together.
Some counts may be expressed with the ply number missing e.g. 16 nm. When a count is expressed like this it is assumed the ply is 1.
The twist is not measured within a yarn count as each manufacturer sets this themselves. The twist of a yarn is sometimes expressed separately as twists per inch (tpi) or twists per metre (tpm).
Different measuring systems
There are many different systems used for measuring yarn. I am just going to cover the most common ones in this post.
Count system 
Yarn 
Definition 
Cotton count (cc or ne) 
Cottons 
840 yards/pound 
Worsted count (wc) 
Wools 
560 yards/pound 
Linen count (lea or nel) 
Linen 
300 yards/pound 
Numero metric count (nm or mc) 
Silks 
1000 meters/kilo 
Although the different systems are commonly used for specific yarns they are often used for other types of yarn too. The numero metric count is particularly used across different yarn types.
Imperial counts (cc/wc/lea) are written ply/count
Metric counts (nm) are written count/ply
Working out the yards/pound or meters/kilo
When you know the count of a yarn this enables you to work out how many metres/yards you have per kilo/pound of that particular yarn. To work this out you multiply the number of yards/meters per pound/kilo by the yarn count. Then divide this by the ply. See the table and example below:
Cotton count 
yards per pound = (840 x count) / ply 
Worsted count 
yards per pound = (560 x count) / ply 
Linen count 
yards per pound = (300 x count) / ply 
Numero Metric count 
metres per kilo = (1000 x count) / ply 
For example:
16/2 nm
m/kg = (1000 x 16) / 2
8000 m/kg
2/12 cc
y/lb = (840 x 12) / 2
5040 y/lb
When yarn is plied there is a little bit of take up so the amounts may not work out exactly but in thinner yarns this is negligible.
Being able to do this calculation is so useful because it enables you to work out how much yarn you are going to need for your project.
It is also useful to be able to convert between the two:
y/lb to m/kg multiply by 2.016
m/kg to y/lb multiply by 0.495
(these are rounded to three decimal places)
For example:
5040 y/lb x 2.02 = 10160.64 m/kg
Being able to do this calculation is so useful because it enables you to work out how much yarn you are going to need for your project.
To convert directly between metres and yards, use the following calculation:
Metres to yards multiply by 1.09
Yards to metres multiply by 0.91
Twist and Ply