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Introduction
Retail designers are always looking for a way to make
their products unique and this definitely applies to sewing denim
garments. From a thread perspective, this can include: |
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Using contrast
color threads: |
- For
different operations.
- For
different needles of the same operation
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Using threads that
will maintain their color regardless of the wash process:
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- Using a 100%
polyester thread dyed with disperse dyes.
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Using threads that
will wash-down depending on the severity of the finishing process:
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- Using a
cotton wrapped core thread.
- Using an
true indigo or faux indigo dyed cotton wrapped core thread.
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Using a thread
that looks different that regular stitching thread: |
- Shiny thread
like Signature Plus® or J Metallic™.
- Two-color
thread like Design-A-Core®.
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Using different thread sizes that give a bolder stitch appearance. |
Larger Thread
Sizes that Give Bolder Topstitch Appearance
Years ago, the most
common size of thread used for topstitching denim was a Tex 60,
80, or possibly Tex 105 size threads. Recently, many manufacturers
have graduated to a Tex 120 size thread to give a slightly bolder
stitch appearance. Today, many denim designers are looking at much
heavier thread sizes including Tex 150, Tex 180, Tex 240, and even
Tex 300.
This has created problems for many denim garment manufacturers
because their normal denim sewing machines were not designed for
these heavier threads. |
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Tex Size = Gram Weight Per 1000 meters of non dyed yarn. See the
World Wide Size
Comparison Chart for yarn size conversion. |
What Determines the Thread Size that Can
Be Sewn on a Sewing Machine
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301 lockstitch machines, the maximum needle thread size that can
be sewn is usually determined by the capacity of the hook or
shuttle in the machine and the size of the needle being used. There must be enough clearance between the bobbin case holder and
the hook base to allow the thread to move freely around the hook
during the stitch formation. Sometimes, an older hook will work
better on larger threads because it has more play in the raceway
allowing for more clearance for the thread. |
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Regular Single Needle Lockstitch Machine |
Hook Base
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Basket
(Bobbin Case Holder)
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The hook must also
accommodate the use of larger than normal needles. In some cases,
the retainer or gib of the hook is shaped differently to allow the
thread to pull out of the hook with less resistance. Note that the
hook must be properly lubricated. |
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Many sewing machine
companies do make higher capacity hooks that will allow larger threads
to be sewn, but these are generally very expensive. |
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Heavy Duty, Single Needle Lockstitch Machine
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There are also machines designed for sewing very heavy threads
used for sewing upholstered furniture and leather goods. Some
manufacturers are purchasing these types of machines so they can
sew extra large thread sizes up to Tex 500 or Tex 600 thread
sizes. |
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Another option for sewing
heavy threads on 301 lockstitch machines is to sew the heavy thread in
the bobbin and using a regular size thread in the needle. This means
that the seam is inverted when it is sewn. This is a common practice
when setting front pockets or outlining the fly on a 5-pocket jean.
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It is easier to use heavier thread sizes in the needle position of chainstitch machines; however, even these machine sometimes must
be modified to allow the thread to be pulled up from under the
needle plate with the least amount of resistance. This may include
increasing the size of the needle hole in the needle plate. |
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Recommended Needle Sizes for Heavy Threads
Most manufacturers who
are sewing heavy denim are using a size 140 needle. When sewing
heavier thread sizes, larger needle sizes must be used. Note: Many
times using a larger needle size will increase the occurrence of
fabric damage and broken stitches due to needle-cutting.
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Thread Tex Size |
Minimum Needle Size (Metric) |
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Tex
150 - Tex 135 |
140 |
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Tex 150 |
150 |
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Tex 180 |
160 |
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Tex 240 |
200 |
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| A
simple test to determine if the needle and thread are compatible
is to thread the needle with about 12 inches of thread. Hold the
thread fairly taught, at a 45-degree angle, and with a circular
motion make the needle twirl around the thread. As the twirling
motion of the needle slows down, the needle should slide freely
from the top to the bottom of the suspended thread. If the needle
does not slide easily, then sewing problems will probably result. |
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Thread
Tension Required for Heavy Thread Sizes
Generally, a heavier
thread size will require more thread tension to properly set the
stitch on denim fabric. The heavier the sewing thread being used, the
more needle thread machine tension that will be required. Lockstitch
machines will also require heavier take-up spring pressure.
Also, all of the thread guides and eyelets may need to be used to help
control the thread during the sewing cycle. This will also help to
keep “French” knots from forming in the thread path that can restrict
the proper flow of thread to the needle.
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