Thread is on every costing sheet and rarely measured. It is usually a flat figure carried over
from the last style, because nobody has unpicked a seam to see how much went into it. It is
not a large cost. It is, though, one that can be measured in ten minutes, and the
measurement tells you how many cones to order.
The sum
Thread per garment
(seam length × metres of thread per metre of seam, for each seam type, added up) plus
an allowance for what is lost at the ends and in re-threading.
Two numbers go into it for each type of seam, and both come from the garment, not from a
table: the seam length, which is the sum of the stitched seams measured with
a tape, and the ratio, which is how much thread went into one metre of seam.
How to measure the ratio
- Stitch one metre of the seam on the machine you use, with the stitch length you use.
- Unpick it and pull the thread straight. For a lockstitch, measure the needle thread and
the bobbin thread. For an overlock, measure every thread.
- Add the lengths. That is the ratio for that seam type. Do it once per seam type; a
lockstitch and an overlock use very different amounts.
A worked example
These figures are made up to show the sum. They are not a benchmark and not a claim about any
garment. Say a shirt has 12 metres of lockstitch seam and 6 metres of overlock seam, and
that unpicking sample seams gave a ratio of 3.5 for the lockstitch and 14 for the overlock.
- Lockstitch: 12 × 3.5 = 42 metres.
- Overlock: 6 × 14 = 84 metres.
- Together: 126 metres.
Add an allowance for the ends of seams, thread left on the cone and re-threading. Take 8%,
also an assumption: 126 × 1.08 = 136.08 metres a garment.
From metres to rupees and cones
Say a cone holds 5,000 metres and costs ₹90. A metre costs ₹0.018, so one
garment's thread costs 136.08 × ₹0.018 = ₹2.45.
For an order of 1,000 garments: 136.08 × 1,000 = 136,080 metres, which is
27.2 cones. Order 28, and the order is covered with a little to spare.
How small is it?
Against the ₹640 direct cost in the
costing example, ₹2.45 is
0.38%. The number is small, and that is a finding too: thread is not where
a garment's cost is made or lost.
What an error does is easier to see in cones than in rupees. If the real ratio is 20% higher
than you assumed, each garment uses 163.3 metres instead of 136.08, which is ₹0.49 more.
On 1,000 garments, that is 5.4 cones — the difference between an order that is
finished and one that stops for a delivery.
Measure it to order it, not to price it
The rupee figure will hardly move a price. The cone count decides whether the line runs out
of thread on the last day of an order.
What the sums leave out
- A made-up ratio, seam length and allowance. All three are assumptions in
this example. Measure your own.
- Different threads for different jobs. Topstitching, buttonholes and
bar-tacks use their own thread, sometimes a heavier one, at its own price. Count each.
- Machine settings. A longer stitch uses less thread per metre, and a
different tension may change the bobbin figure. Re-measure when settings change.
- Thread broken and wasted. The allowance has to cover it; if rework is
high, look at the rejects and rework article.
Put the thread cost into the costing calculator as part of the
direct cost, and the cones into your purchase list. For the fabric half of the same
question, the fabric consumption article
does the same job with metres of cloth.