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Fundamentals of Household Sewing Machines
Janome Sewing Machine Co., Ltd.
TABLE OF CONTENTS
Page
Chapter 1
History of the sewing machine ------------------------------------------------------------------------ 3
Chapter 2
Types of sewing machines
1. Classification by sewing purpose-------------------------------------------------------------- 4
2. Classification by method of stitch formation ------------------------------------------------ 4
3. Classification by control method-----------------------------------------------------------5 - 7
Chapter 3
Fundamentals of sewing
1. Fabrics--------------------------------------------------------------------------------------------8 - 9
2. Sewing machine threads ---------------------------------------------------------------------- 10
3. Sewing machine needles-----------------------------------------------------------------11 - 14
4. Presser feet --------------------------------------------------------------------------------- 15 - 18
Chapter 4
Lock stitch sewing machines
1. Principles of machine sewing----------------------------------------------------------- 19 - 23
2. Hook race------------------------------------------------------------------------------------------ 24
3. Common sewing problems: causes and remedies------------------------------- 25 - 40
Chapter 5
Household overlock sewing machines
1. Introduction to overlock mechanism-------------------------------------------------- 41 - 42
2. Guide to overlock stitches --------------------------------------------------------------- 43 - 47
Chapter 6
Glossary of household sewing machine terminology
1. Stitch and sewing method terminology ---------------------------------------------- 48 - 51
2. Terms for household sewing problems ---------------------------------------------- 52 - 54
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Chapter 1: History of the sewing machine
1. 1589: Mr. William Lee of Britain, having watched his wife knit, wonders if he could make a mechanical knitting machine and thus begins research into creating a mechanical sewing machine.
2. 1790: Mr. Thomas Saint of Britain invents the chain-stitch sewing machine equipped with the basic
functions of a sewing machine.
3. 1834: Mr. Walter Hunt of the U.S.A. invents the lock stitch machine which uses two threads. He is the originator of the lock stitch sewing machine with upper and lower threads
4. 1844: Mr. Elias Howe and Allen Wilson of the U.S.A. succeed in the assembly of the first working sewing
machine using a needle with a hole at the tip. 5. 1850: Mr. Isaac Singer of the U.S.A. makes improvements on this sewing machine and goes on to
develop the basis of current sewing machines.
6. 1854: Mr. Edward Clark, a vice president at the Singer Sewing Machine Company, introduces the installment-sales system, and contributes to widespread growth in sewing machine sales.
In Japan, a sewing machine is among the gifts to the Japanese government when American Admiral Matthew Perry and the Black Ships make their second visit to Japan.
7. 1856: Mr. James Gibbs of the U.S.A. invents the single chain-stitch sewing machine and becomes a
globally famous maker. 8. 1869: Mr. Tetsuzo Sakoku, a Japanese gun maker, makes the first Japanese sewing machine, a chain
stitch sewing machine. 9. 1924: In Japan, the Pine Sewing Machine Factory starts manufacturing a household sewing machine. * 1957: Janome produces the first Japanese zigzag sewing machine. * 1979: Janome produces the first Japanese computerized sewing machine.
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Chapter 2: Types of sewing machines 2.1 Classification by sewing purpose
2.1.1 Household sewing machines
These sewing machines are mainly used for general sewing purposes at home. Operation is usually at 700 to 1,000 stitches-per-minute (spm). These sewing machines can sew straight stitches, zigzag stitches, stretch stitches, buttonholes and/or embroidery designs.
2.1.2 Professional-use sewing machines These are sewing machines for tailors, sewing school students, etc. who are not satisfied with a
household sewing machine. A more durable machine, they normally have a maximum speed of around 1500 spm.
2.1.3 Industrial sewing machines This type of sewing machine is used in the manufacture of clothing, for example work clothes or
uniforms, ready-to-wear clothing, etc. Unlike the household sewing machines, which can do various types of stitches, industrial sewing machines are dedicated to one task such as straight stitching or button sewing, to increase efficiency.
speeds of around 3000 spm or higher.
2.2 Classification by method of stitch formation Fabric
2.2.1 Chain stitch machines (overlock machines) As shown in the figure, sewing is accomplished with one thread.
The name chain stitch sewing machine comes from the formation of a chain on the underside of the fabric. Although continuously sewn with one thread, the stitching tends to expand and loosen, and if one place becomes unraveled, the rest will continue to unravel. Stitch on the wrong side
Examples of use include sewing paper bags such as those for cement or the seams of umbrellas.
2.2.2 Straight lock stitch sewing machines Fabric
As shown in the figure, the threads of the upper and lower sides are intertwined in the middle of the fabric thickness. Since stitches are formed securely and neatly without the worry of unraveling, they enjoy widespread use and are the machine of choice for general garment sewing.
2.2.3 Zigzag lock stitch sewing machines
Fabric As shown in the figure, a lock stitch sewing machine can sew stitches ranging from simple zigzags to sophisticated, automated patterns.
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2.3 Classification by control method 2.3.1 Electric sewing machines These start and stop by pressing a foot controller and speed is adjusted by the degree to which the
foot controller is pressed. There are also models which start and stop with a finger-pressed button. With this type of sewing machine, it is not possible to set what the position of the needle will be when
the sewing machine stops. 2.3.2 Electronic sewing machines These include types where speed can be controlled with a lever, speed can be controlled from slow
to incrementally faster, speed can be set to match the user’s preference or the machine is operated with a button. With this type of sewing machine, it is possible to set the position of the needle to be either up or down when the sewing machine stops.
2.3.3 Computerized sewing machines In addition to the functions of an electronic sewing machine, these sewing machines have various
functions automated through a built-in microcomputer. 2.3.4 Computerized embroidery sewing machines These are equipped with an embroidery function in addition to the functions of a computerized
sewing machine. There are two ways this embroidery function may be accomplished: either through a separate,
attachable embroidery device or built-in to the sewing machine.
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Electric sewing machine (oscillating shuttle hook)
Electric sewing machine (horizontal full rotary hook)
Feed cam
Upper shaft crank
Stitch length dial
1) Upper shaft
4) Thread
take-up lever
2) Needle bar
mechanism
6) Feed lifting mechanism
3) Hook driving mechanism
5) Feed rocking device
7) Drop feed device
Oscillating shuttle hook
Timing belt
Thread take-up lever crank
4) Thread take-up lever
2) Needle bar device
6) Feed lifting device 5) Feed rocking device
7) Drop feed device
Stitch length dial
1) Upper shaft
3) Hook driving device
Horizontal full rotary hook
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Computerized sewing machine (lock stitch mechanism)
Needle bar device
Feeding device
Stitch length control device
Stitch width control device
Computerized embroidery sewing machine (embroidery mechanism)
Y-axis directional control mechanism
X-axis directional control mechanism
Carriage
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Chapter 3: Fundamentals of sewing 3.1. Fabrics 3.1.1 Types of fibers
There are both natural and manufactured fibers. a) Natural fibers Naturally occurring fibers, which includes vegetable, animal and mineral fibers, are classified as
follows: ┏━ Vegetable fibers ━━┳━ Cotton ┃ ┃ ┃ ┗━ Hemp Natural ┃ fibers ╋━ Animal fibers ━━┳━ Silk ┃ ┃ ┃ ┗━ Wool ┃ ┗━ Mineral fibers ━━━━ Asbestos
b) Manufactured fibers
Manufactured fibers are those fibers manufactured using chemical compounds to either render natural substances into fibers or to produce the fibers themselves, and are classified into regenerated, semi-synthetic, synthetic, and inorganic fibers as follows.
┏━ Regenerated ━┳━ Rayon ┃ ┣━ Cuprammonium rayon (Bemberg) ┃ ┗━ Polynosic ┣━ Semi-synthetic ━┳━ Acetate ┃ ┣━ Triacetate ┃ ┗━ Pro mix ┣━ Synthetic ━┳━ Nylon
Manufactured ┫ ┣━ Polyester fibers ┃ ┣━ Acrylics ┃ ┣━ Poly Vinyl Alcohol (PVA) ┃ ┣━ Polyurethane ┃ ┣━ Polypropylene ┃ ┣━ Polyethylene ┃ ┣━ Polyvinyl chloride ┃ ┣━ Vinylidene chloride ┃ ┣━ Polychlal ┃ ┗━ Benzoate ┗━ Inorganic ━┳━ Glass ┗━ Carbon
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3.1.2 Characteristics of various fibers 1) Cotton ------- Major producers: United States, Mexico, India, and Egypt ･ Wrinkles easily. ･ Has soft, nice feel and is highly absorbent; suitable for underwear. ･ One of the less expensive fibers, it is utilized for every-day clothing.
2) Linen--------- Major producers: Russia, Belgium, and Poland ･ A sturdy, hard fiber that wrinkles easily ･ Has 1.6 times the strength of cotton and about 1.5 times that of silk ･ Highly absorbent yet dries quickly and is cool, making it optimal for summer garments. 3) Silk ---------- Major producers: Japan, China, South Korea, and Russia ･ Has refined gloss and suppleness, and resists wrinkles ･ Can be woven into thin tight cloth, has good absorbency, and is also quick-drying
･ Although expensive, optimal for formal clothing
4) Wool --------- Major producers: Australia, New Zealand, Russia, Argentina, United States, and China
･ Has highest moisture absorbency among fibers; although fibers expand with humidity, is also highly water repellant
･ Retains warmth well; since wool does not burn easily, used for carpet ･ Widely used as a clothing material
5) Rayon --------Ingredients: Wood pulp, cotton linter, sodium hydroxide, and sodium sulfate
･ Since rayon fiber consists of cellulose, overall characteristics similar to cotton or linen ･ Inexpensive and good stainability ･ Liked for its soft appearance; widely used for shirts, blouses, and dresses 6) Acetate------ Ingredients: Wood pulp, cotton linter, acetic anhydride, and acetone ･ Has rich gloss; also has good body and stretch ･ Lacks strength when pulled or bent ･ Used for suiting, sweaters, curtains, etc. 7) Nylon -------- Ingredients: Oil (adipic acid, hexamethylenediamine) ･ Light and strongest among fibers; gradually weakens and yellows in sunlight ･ High stretch and flexibility; resists wrinkles ･ Wide range of uses 8) Polyester --- Ingredients: Oil, natural gas (terephthalic acid, ethylene glycol) ･ Very strong fibers, highly flexible and resists wrinkles; low deterioration in sunlight ･ Poor stainability and also tends to generate static electricity ･ Easily becomes soiled or discolored if washed with heavily soiled or non-colorfast items ･ Wide range of usage from garments to industrial use
9) Acrylics------ Ingredients: Oil, natural gas (acrylics nitril), VCM/PVC, acetic acid vinyl, and methyl vinyl pyridine
･ Lightweight; airy and soft; has warm touch; tends to generate static electricity ･ Increasingly replacing wool in garments 10) PVA --- Ingredients: Oil, natural gas (polyvinyl alcohol), and formaldehyde
･ Has highest moisture absorbency among synthetic fibers; Appearance is hard and easily wrinkles
･ High durability; excellent weatherability; a light fiber ･ More industrial usage than in garments 11) Polyurethane --- Ingredients: Oil, diisocyanate, and hydrazidine ･ Has flexibility and stretch like rubber; can stretch 500 – 800% ･ Stronger and better stainability than rubber; can be made into fine threads ･ More commonly called spandex; usually mixed with other fibers
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3.2. Sewing machine threads The structure and characteristics of the sewing thread used greatly influence the performance of a
sewing machine. 3.2.1 Kinds of sewing threads Thread is categorized into 2 kinds depending on the type of fiber. There are short (staple) and long (filament) fibers, and either may be chosen depending on the
purpose.
1) Staple Generally called span thread, this thread has a slightly fluffy surface and is formed from
comparatively short fibers pulled parallel, and then twisted and strengthened. In use, it has volume and works well in sewing machines. A more economical thread, it is
widely used for garments. ･ Span polyester sewing thread ･ Soft cotton thread ･ Polyester overlock thread ･ Jeans thread (polyester and cotton) 2) Filament Generally called filament yarn, this thread, which has a glossy surface, is formed from several
very long continuous fibers pulled parallel, and then twisted and strengthened. Used for embroidery and decorative sewing. ･ Janome embroidery thread (acrylics) ･ King Star embroidery thread (polyester) ･ Resilon thread (nylon) ･ Silk thread 3.2.2 The twist in sewing machine threads A twist is applied to the thread to increase the suture power of the fibers and make the overall
thread stronger. Depending on the direction it is twisted, thread is said to be either Z twist (left twist) or S twist (right twist). All sewing machine threads are Z twist, and hand-sewing threads are S twist. Z twist thread is used as sewing machine thread because of how the stitches are formed by the shuttle or rotary hook.
If S twist thread is used in a sewing machine, the thread would untwist, fall apart, and break.
On the other hand, there are no major problems if Z twist thread is used for hand sewing.
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3.3. Sewing machine needles Sewing machine needles can be roughly divided into household (including those for household
overlock machines) and industrial (including professional use). The main elements of the sewing machine that form a stitch are the needle, the shuttle or rotary hook,
the thread take up lever, the feed, the presser foot, and the thread tension. Of these, the needle is an important element which greatly affects seam quality and the ability to obtain good thread tension.
3.3.1 Names of needle parts and description of dimensions
The names of each part of a sewing machine needle are shown in Fig. 1. A description of commonly used dimensions is shown in Fig. 2.
3.3.2 Explanation of m1) Dimension D
The distance betwe The dimension D is
2) Dimension B Represents the thic
Organ or Schmetz
Size Organ n
7911141618
Fig. 1 Needle parts
A: Shank thickness B: Blade thickness C: Flat-side width D: Distance between needleeye and end of shank E: Full length F: Head length H: Scarf length J: Needle eye length K: Needle eye width N: Shank length Z: Long groove depth S: Hollowed-out thickness
.
Fig. 2 Needle dimensions
ajor dimensions
en the upper end of the needle eye and end of the shank fixed even if needle size (thickness) changes.
kness of the blade. The indication varies depending on the brand of needle, Indications are as shown below.
indication eedle Schmetz needle
Blade thickness (mm)
55 0.57 65 0.67
75 0.77 90 0.92 100 1.02 110 1.12
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3.3.3 Sewing machine needle varieties, purposes and features Sewing machine needles are classified by symbol according to the kind of sewing machine to be
used and the sewing purpose. The classification symbol varies depending on the needle manufacturer, such as Organ Needle, Schmetz, and Singer. The classification symbol descriptions in this chapter are as specified by the Japanese Industrial Standards and Organ Needle Co., Ltd.
1) HA x 1 (15 x 1)
<Purpose>
General purpose household sewing needle
<Features> Planar shaving of the shank is performed so that the direction of the needle may not be mistaken
when inserting the needle.
<Applicable models> ･ All Janome household sewing machines ･ Industrial embroidery-only machines
2) HA x 1 SP (Janome’s Blue tip needle is the same as HA x 1 SP, size 11.)
<Purpose> Prevents skipped stitches in stretch fabrics, such as knitting and tricot. <Features>
Features (1) - (3) prevent skipped stitches caused by the fluctuation of the fabric of knit or elastic, and (4) prevents the fabric thread from being broken.
(Feature 1) The width at the needle eye (B0) is wider than the blade (B1) so that while the needle is penetrating fabric, the amount of movement of the cloth up and down the needle according to rise and descent of the needle is minimized.
HA x 1 SP
HA x 1
B0 B1
B Skipped stitches are prevented since the needle thread loop is formed properly without
the fabric lifting substantially as the needle rises during needle thread loop capture, and the loop can be properly caught by the tip of the hook.
HA x 1 SP
Needlethread
Minimal cloth fluctuation because the blade is thin.
1) Needle 2) Lowest 3) Capture penetration needle of needle begins. position thread
Fabric
Tip of hook
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(Feature 2) A protuberance for enlarging the needle thread loop is in the needle eye portion. HA x 1 HA x 1 SP
ProtuberanceLarger needle thread loop
Cross-section of needle
(Feature 3) In order to bring the needle close to the tip of the hook, the diameter (S) is made smaller than a standard needle.
(Feature 4) To prevent breakage of fabric threads, the tip of the needle is made ball-point. (The needle tip is rounded.)
Regular point Ball-point
<Applicable models>
･ Janome overlock machines and household sewing machines
3) HA x 3N
<Purpose> Household sewing machine needle for preventing skipped stitches <Features> Has a protuberance about half the size of the HA x 1 SP at the upper part of the needle eye to
prevent skipped stitches. The basic structure is the same as the HA x 1 needle. <Applicable models> ･ For embroidery models, sold as Red Tip Needle ･ Developed exclusively for Janome
4) EL x 705
<Purpose> Sewing machine needle for chain stitches <Features>
It has a planar shaved shank like the HA x 1. There is also a long groove in the back of the needle.
<Applicable models> ･ Janome CoverPro series (900CP and 1000CP)
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5) HL x 5
<Purpose> Professional sewing-machine needle <Features> ･ Has a planar shaved shank like household sewing machine needle HA x 1. ･ Blade is reinforced to increase needle strength. Strength is similar to the DB x 1 needle for professional and industrial use. <Applicable models> ･ 1600P (High speed straight stitch sewing machine)
6) DB x 1
<Purpose> General purpose professional and industrial sewing machine needle <Features> ･ Blade is reinforced to increase needle strength. ･ Has no planar shaved shank unlike household sewing machine needles. ･ Diameter of the shank varies depending on the size of the needle. Sizes 7 through 18 have a 1.62 mm shank <Applicable models> ･ 1600P-DB and 1600P-DBX (High speed straight stitch sewing machines)
7) Remarks: There are about 2,000 different kinds of needles for industrial sewing machines. Factoring in the
shape of the tip and surface treatment, the number increases exponentially.
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3.4 Presser feet
Beautiful sewing results can be obtained by using the correct presser foot for the purpose at hand. Here are some typical presser feet:
1) Zigzag foot, A
Used for basic sewing, straight, zigzag, etc.; has a transparent window for easy stitching.
2) Straight stitch foot, H Useful for sewing straight stitches more finely
without the fabric puckering.
3) Satin stitch foot, F Good for sewing dense stitches evenly
without stacking.
4) Overcasting foot, C For sewing fabric edges; the brush attached
to the presser foot prevents skipped stitches
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5) Auto buttonhole foot, R Simplifies buttonhole sewing. Button is set in the guide to make a
buttonhole of suitable size for the button.
6) Button sewing foot, T For attaching buttons; place the button under
the button sewing foot, adjust the stitch width for the button and sew.
7) Zipper foot, E Specifically designed for attaching zippers;
simplifies zipper attachment
8) Embroidery foot, P This foot is used exclusively for embroidery
sewing.
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9) Blind stitch foot, G Used for hemming of trousers, etc.; Grooves
on the reverse side of the presser foot prevent the fabric from slipping out from under the blind stitch foot.
10) Hemmer foot, D Makes a triple fold in the edge of the fabric;
optimal for finishing the edges of skirts, shirts, etc.
11) Darning foot Used for quilting, etc.; fabric can be moved
freely to make hand-sewn-like curves; convenient for making borders around designs and darning.
12) Even feed foot Upper and lower feed dogs feed the fabric to
prevent the slippage of layers especially when quilting layers or sewing stretch material.
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13) Ultra Glide foot An ultra glide resin allows fabrics, which tend
to stick (leather, vinyl, etc.) to feed smoothly. 14) Cording foot (3-way) The guides on the presser foot allow cording
to be done neatly and in parallel rows. 15) 1/4 inch seam foot Guides edge of fabric to make 1/4 inch
(6.4mm) seams; patchwork, which requires sewing many layers, can be done easily and quickly.
16) Beading feet Makes beading easier; the groove on the foot
guides beads smoothly.
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Chapter 4: Lock stitch sewing machines 4.1 Principles of machine sewing
4.1.1 Stitch formation with the lock stitch sewing machine Two threads, the needle thread and the bobbin
thread, are used and at every stitch the needle thread is intertwined around the bobbin thread. The same stitch formation appears on the right and wrong sides. The lock stitch is widely used since the seam does not come unraveled easily and two or more layers can be sewn securely.
4.1.2 The role of each part in making a stitch
Bobbin
Bobbin thread
FabricNeedle thread
Needle
Fabric Bobbin thread
Needle thread Needle1) The role of the needle
The needle carries the needle thread, which is above the fabric, to the wrong side of the fabric.
2) Role of the hook
The hook intertwines the needle thread with the bobbin thread.
Fabric
Loop
Bobbin threadHook
Needle thread
Bob
Needle thread
* If the hook does not catch the loop, a skipped stitch will occur.
bin thread
BobbinLoop
Tip of hook
a) The tip of the hook catches the loop of the needle thread.
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Needle platethread
Bobbincase
b) The hook intertwines the bobbin thread.
3) Role of the thread take-up lever
Bobbin case
Needle thread
Hole of the presser foot Presser foot
Bobbin thread
Hook
Thread take-up lever
The thread take up lever tightens the loop of the needle thread after the hook passes through.
Fabric Needle plate 4) Role of the feed dog
The feed dog feeds the fabric.
Feed dog
Fabric
4.1.3 Conditions required to successfully make and catch the loop
1) Making a loop Since a needle-thread loop is made using the friction between the fabric and the thread, the pressure with which the fabric is pressed down is important to obtaining a stable loop.
･ A needle-thread loop is made from friction between the fabric and thread. When a needle goes up from the lowest point, thread is pressed down by the fabric and a loop
is formed.
Needle goes up. Lowest point of needle
Loop Fabric
Needle Needle thread
Bobbin thread
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* Condition of the loop when fabric is too loose a) Since the fabric moves up and down together with the needle, a loop is not made. (It occurs
often in stretch fabrics). b) If the fabric is pressed down firmly a proper loop can be made.
Needle moves distance δ1.
δ1
Loop
ＯＫ ＮＧ
a b
Needle at the lowest point a b
h Fabric
b
* Needle and presser foot selection is important.
a
2) The amount of needle displacement, the needle depth, and clearance between needle and
hook are all conditions that need to be met in order to catch a needle thread loop by the tip of hook.
* The amount of needle displacement (decides size of the loop)
Expressed by the amount the
needle rises from the lowest point of the needle until the tip of hook meets the needle.
Example: L = 1.7mm
R = 3.4mm
* Needle depth (decides Y-axis position of the loop)
The distance the needle moves between the hook at the left side of the needle until the upper edge of the needle eye meets with the edge of the hook.
Amount of movement of the needle
Needle at the lowest point
Example: L = 3.2mm R = 1.8mm
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Amount ofneedle movement
* Clearance between needle and hook
Clearance
Loop
Tip of hook
(decides X-axis position of the loop) The amount of clearance between needle
and tip of hook (A master needle should be used to adjust.)
Example: between -0.05 and +0.1 mm
4.1.4 Stitch formation 1) Vertical oscillating hook
A) The tip of the hook catches the needle thread
loop.
Needle thread
Bobbin thread
Loop
Bobbin case
Needle plate
Fabric
B) The needle-thread loop is made to pass around the
bobbin thread (bobbin case) by an inner shuttle or rotary hook.
C) The loop of the needle thread, having passed around
the bobbin case, is tightened.
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2) Magnetic horizontal full rotary hook A) As the needle goes up, the tip of
the hook race catches the needle-thread loop when the hook comes behind the needle.
B) The needle-thread loop caught by the
tip of the hook is made to pass around the bobbin thread (or bobbin).
C) The loop of the needle thread, having
passed through the bobbin holder, is tightened.
Bobbin thread
Needle thread
Needle thread
Bobbin holder Bobbin thread Tip of hook
Needle-thread loop
Rotary hook
Bobbin thread
Needle thread
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4.2 Hook race 4.2.1 Vertical oscillating hook The traditional and commonly used hook
race; since the shuttle hook oscillates, measures are required to counteract the noise created by the shuttle. Janome’s oscillating shuttle hooks are among the finest in the world.
4.2.2 Vertical full rotary hook A high speed full rotary hook developed by Janome; the eccentric driver and automatic opener drew much attention from both the sewing industry and the general public. A large size model of this hook was even made into a popular exhibit at the Science Museum of Tokyo. However, there has been a shift to using the horizontal full rotary hook, and this type of hook is no long being used.
Shuttle hook
Bobbin
Shuttle race ring
Shuttle race body
Bobbin case
Bobbin HookHook race ring
Hook race body
Bobbin case
4.2.3 Magnetic horizontal full rotary hook A quiet, jam-free magnetic hook developed by Janome; it is used in electronic and computerized sewing machines.
Hook race
Bobbin holder
Bobbin
Bobbin4.2.4 Industrial vertical full rotary hook Hook race Bobbin case This hook used for professional and industrial sewing machines including Janome’s high speed straight stitch sewing machines.
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4.3 Common stitch problems: causes and remedies 4.3.1 Skipped stitches
Skipped stitches(1)
№ Cause Remedy
1
Improper needle displacement
If the amount of needle displacement is outside the standard range, it will become the cause of skipped stitches. If the amount of needle displacement is too small, the loop will be made too small. Since the tip of the hook cannot catch the loop, the stitch will be skipped. On the other hand, if the amount of needle displacement becomes too large, the loop will become excessively large, collapse and cause skipped stitches.
Needle displacement Needle displacement
too small too large
1) Check whether the amount of needle
displacement is appropriate. Before checking, make sure that the needle drop positions (left and right) are within their standard ranges.
2) Standard needle displacement: * Vertical oscillating hook sewing
machines: Left (L) needle position: 1.7 ± 0.3 mm * Horizontal full rotary hook sewing
machines Left (L) needle position: 3.4 ± 0.15 mm * Vertical full rotary hook sewing machines Center needle position: 2.0 ± 0.2 mm
2
Improper needle bar depth
If the needle bar is too deep, the tip of the hook will catch above the loop. If the needle bar is too shallow, the tip of the hook will catch below the loop and it will cause skipped stitches.
Needle bar Needle bar too deep too shallow
1) Check whether the needle bar depth is
appropriate. Before checking, make sure that the needle is inserted until it touches the stopper.
2) Standard needle bar depth:
Vertical oscillating hook sewing machines Left (L) needle position: 3.2 ± 0.3 mm
Horizontal full rotary hook sewing
machines Left (L) needle position: 1.8 ± 0.2 mm Vertical full rotary hook sewing machines Center of the hook: 1.8 ± 0.3 mm
Tip of hook
Tip of hook
Tip of hook
Tip of hook
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Skipped stitches (2)
№ Cause Remedy
3
Improper clearance between needle and hook
If the clearance between the needle and hook is too large, the hook cannot catch the loop and it will cause skipped stitches.
Note: The clearance between the needle
and hook is small. Should the tip of the hook and the needle come into contact, the needle may become bent or broken.
1) Check whether the clearance between the needle and hook is appropriate. Before checking, make sure that the needle is not bent.
2) Standard clearance between the needle and hook:
Vertical oscillating hook With HA x 1 size 14 needle: Between -0.05 and +0.1 mm Horizontal full rotary hook With HA x 1 size 14 needle:
Between -0.1 and +0.05 mm Zigzag sewing machines should be
checked at the right and left needle positions.
Vertical full rotary hook DB x 1 /HL x 5 size 14 needle: Between 0 and 0.1 mm -0.05 mm and +0.1 mm HA x 1 needle DB x 1/HL x 5 needle (Oscillating hook)
4 Improper needle threading
Since the force of the thread will increase and the direction from which the thread is drawn change if not threaded properly, a proper loop cannot be made and it will cause the stitch to be skipped.
1) Rethread as shown in the instruction book.2) The delivery of the thread from a spool
should be counter-clockwise.
5 Improper needle insertion 1) If needle is not attached deeply enough, it
will create the same condition as having the needle bar too deep and it will cause skipped stitches.
2) In case of the DB x 1 needle, since the
shank portion is round, depending on how it is attached, the needle eye may become out of alignment and cause stitches to be skipped.
1) In case of the HA x 1 needle, the planar portion of the shank should face the needle bar slot.
1) In case of the DB x 1 needle, the needle
eye on the short groove side should be at a right angle to the tip of the hook.
Correct Wrong Wrong 3) Insert the needle until it touches the
stopper pin of the needle bar.
Standard outer diameter of needle
Standard bottom of scarf
0 - 0.1mm
Needle
Needle bar
Needle eye Tip of hook
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Skipped stitches (3)
№ Cause Remedy 6 Bent or dulled needle tip
1) If the needle is bent, the clearance between
needle and hook will vary and it may cause stitches to be skipped.
2) If the needle tip is dulled, the needle will be bent
when penetrating the fabric and the clearance between the needle and hook may become large, and it will cause skipped stitches.
1) Place a needle on a flat surface and check that the blade of the needle is parallel.
2) Check if the needle point is dulled or
burred. OK Dulled Burred 3) When a needle is found to be
damaged as mentioned above, replace with a new needle.
7 Dulled or burred hook
If the hook is dulled or burred, it will create the same conditions as having the clearance between the needle and hook too large and it will cause of skipped stitches.
Normal shape of hook tip
1) Replace dulled or burred hooks with a new one.
Note: Since the tip of the hook is
tempered and thus very hard, it cannot be repaired.
Burred Dulled
8 Misalignment of needle drop with the hole of the needle plate
When the needle drop is misaligned with the hole of the needle plate, the needle tends to bend into the hole when penetrating the fabric causing the clearance between the needle and hook to become too large, and it will cause skipped stitches.
1) The clearance around the needle and the hole of the needle plate should be at least 0.2 mm.
9 Improper presser-foot pressure
If presser foot pressure is weak, the fabric will fluctuate with the movement of the needle, the loops will collapse, and it will cause skipped stitches.
1) When sewing thick fsewing machine withpressure, set the preto 3 (maximum).
+0.01
-0.05δ ＝ 0.1 mm
0.2 mm or more
L needle position
0.2 mm or more
0.2 mm or more
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R needle position
Needle plate hole
ab as
0.2 mm or more
rics using a djustable foot
ser foot pressure
Skipped stitches (4)
№ Cause Remedy
10 Using hand-sewing thread or inferior thread 1) If S twist thread for hand sewing is used for
machine sewing, the thread will re-twist to prevent a proper loop from being made, and it will cause skipped stitches.
2) If inferior thread is used for sewing, since the
friction on the thread is large, it will re-twist and cause skipped stitches.
1) Check whether Z twist thread is being used.
Z twist (left twist) S twist (right twist) 1) Use quality guaranteed thread that is
designed exclusively for sewing machines.
2) Choose the thread according to the kind
of fabric and thickness you intend to sew.11 Sewing thick fabric
1) When a thin needle is used for thick fabric, the
needle will be bent and the clearance between needle and hook become large and cause skipped stitches.
2) When sewing over a thicker portion the needle
will be bent further and there will be more risk of skipped stitches.
Needle bending at thicker section
Make sure that the needle is not too thin to sew the thickness of the fabric. Reference of needle for fabric thickness Thickness of fabric Size of needle Thin #9 - #11 Ordinary #11 - #14 Thick #14 - #16 Very thick #16 - #18
Note: Only the 1600P series models (high
speed straight stitch sewing machines) are designed to accommodate very thick fabrics.
12 Sewing knit or stretch fabric
Once the needle penetrates the fabric, the fabric will move down and up around the needle according to the down/up movement of the needle. This will cause skipped stitches because the loop does not form properly.
Shape of the loop when sewing stretch fabric
1) Use HA x 1SP (Blue tip needle). 2) In the case of high-speed straight stitch
sewing machines (1600P series models), the needle plate and presser foot made with smaller holes are especially advantageous for thin fabrics.
Thicker portion
Fabric (2 layers)
Tip of hook
Fabric
h
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4.3.2 Breakage of the needle thread Needle thread breakage (1)
№ Cause Remedy
1 Improper needle threading
If the needle thread is not threaded properly, the thread will become tangled along the thread path applying excess tension to the thread and causing the needle thread to break.
1) Rethread the machine as described in the instruction book.
2) Make sure that thread is not tangled along
the thread path.
2 Improperly prepared thread before sewing
If the thread tail is too short and not held down under the presser foot, it will be pulled into the hook causing the needle thread to break.
1) Before starting to sew, draw both threads under the presser foot to the back about 10 cm.
2) For presser feet that have groove(s) (i.e.
buttonhole foot, satin stitch foot), draw both threads to the left before starting to sew.
3 High needle thread tension
If needle thread tension is too tight, the frictional resistance on the thread will increase and cause thread breakage. In particular, this may occur when sewing thick fabric with a thin thread and high needle thread tension.
Adjust the needle thread tension: 1) In straight stitch sewing, the needle thread
and bobbin thread are intertwined in the middle of the fabric thickness.
Correct thread tension with straight sewing 2) In zigzag sewing, the bobbin thread is
intertwined with the needle thread on the wrong side of the fabric about 2/3 the zigzag width.
4 Improperly inserted needle
Needle thread breakage will occur because the tip of the hook cannot catch the loop.
1
5 Bent or dull needles
The clearance between the needle and hook will increase if the needle is bent or dull. As a result, the thread of the loop will be stabbed with the tip of hook, and it will cause needle thread breakage.
1
Bobbin thread
Needle thread Center of the fabric
Needle thread
29
Needle thread
)
)
Bobbin thread
Correct thread tension w Refer to No. 5 on page 2
Refer to No. 6 on page 2
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2/3
ith zigzag sewing 5.
6
Needle thread breakage (2)
№ Cause Remedy
6 Scratches in the bobbin holder (shuttle hook) and/or hook race
If a scratch, a burr, etc. is in the thread path on the hook, or if the surface finish is bad, the needle thread will not pass through the hook smoothly. As a result, thread will jam up in the hook race, and it will cause thread breakage.
1) Check whether the thread path of the hook is smooth and free of scratches.
2) Check whether the tip of the hook is dulled or
burred. Note: If thread breakage occurs because of a
scratch or a burr on the bobbin holder (shuttle hook) or hook race, replace it.
7 Strong needle thread clearance resistance
If needle thread clearance from the hook race is poor, the needle thread will remain under the needle plate as it cannot be pulled out completely, and will cause needle thread breakage.
1) Check that clearance is standard. a) Standard thread-path clearance of a vertical
oscillating shuttle hook
Standard 0.3 - 0.6 mm
b) Standard clearance on the stopper and reverse
stopper for the horizontal full-rotary hook. Center Reverse
Stopper position stopper position c) Standard position of the hook stopper on the
vertical full rotary hook and the thread-path clearance
Distance between spring edge and hook stopper
Center of needle
Bobbin holder The tip is to be below the center line of the spring.
Reverse stopper
0.5 – 0.9 mm Enlargement
This line should belevel.
Bobbin holder
0.3 – 0.6 mm Driver
Shuttle hook
3
Clearance 0.4 – 0.8 mm
t
2)
3)
0 o
Center of inner hook
Check that there are no scratches in the thread path, and finish is smooth. Check that the inner hook (shuttle hook or bobbin holder) rotates smoothly, and there is no resistance as the thread passes through.
Inner hook stopper
Hook stopper spring
f 54
Needle thread breakage (3)
№ Cause Remedy
8 Scratches on the needle hole of the needle plate or presser foot If there is a scratch on the needle hole of the needle plate or the presser foot, thread will wear during sewing and will cause thread breakage.
1) If there is a scratch in the needle hole, replace it.
2) In the case of small scratches, polish using a
polishing agent.
9 Using hand-sewing thread or inferior thread If hand-sewing (S twist) thread or inferior thread is used, it will cause thread breakage as well as skipped stitches.
1) Refer to No. 10 on page 28
10 Using stretchable synthetic thread 1) The force or flow of the needle thread
may make an over-sized or warped loop, and causes thread breakage.
2) When sewing at high speed, the needle
will heat and may melt the synthetic thread and cause thread breakage.
1) Rethread the machine correctly as shown in the instruction book.
2) Sew at a lower speed.
11 Using improper combinations of fabric, thread, and needle
If the type and thickness of the fabric is not taken into consideration when selecting the thread thickness and needle thickness, it will cause needle thread breakage.
1) Check whether the correct combination is being used according to the following table.
Fabric Fabric Thread Needle Thin Gauze,
voile, etc. #80 - #90 #9 - #11
Normal Broadcloth, seersucker, etc.
#60 - #50 #11 - #14
Thick Quilting, 4 layers of denim, etc.
#50 - #30 #14 - #16
Extra heavy
6 to 14 layers of denim, leather, etc.
#30 - #20 DB x 1 #16 - #18
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4.3.3 Bobbin thread breakage Bobbin thread breakage (1)
№ Cause Remedy
1 Incorrect threading of bobbin thread
If the bobbin thread is not threaded properly, the delivery of the thread from a bobbin will be unstable, and the thread will become tangled around the thread-path. As the result, unusual tension will be applied to the bobbin thread, and it will cause thread breakage.
1) Rethread the bobbin thread correctly as shown in the instruction book.
2) Check if the bobbin is set in the shuttle or
bobbin hook correctly.
Horizontal full rotary hook Oscillating hook
2 Insufficient thread preparation before starting to sew
If thread is not threaded properly, it will tangle around the thread path and unusual tension will be applied to the thread. As the result, it will cause thread breakage.
1) Before starting to sew, draw both threads about 10 cm to the back under the presser foot
2) For presser feet that have groove(s) (i.e.
buttonhole foot, satin stitch foot), draw both threads to the left before starting to sew.
3 Inappropriate tension in the bobbin case or bobbin holder
1) If the tension of the bobbin case or
bobbin holder is too tight, the bobbin thread will not draw smoothly and will cause thread breakage.
2) In contrary, if the bobbin thread tension
is too weak, there will be thread tangling caused by too much thread deliveries, and breakage will occur.
1) Standard bobbin thread tension * Oscillating hook
30 g - 50 g with soft cotton thread
* Horizontal full rotary hook 12 g - 15 g (computer sewing machine) with
King brand No. 50 polyester thread * Preset at the factory * High speed straight stitch machines (1600P
series models) 20 ± 5 g including the tension of the pre-tension with No. 50 soft cotton thread
2) The bobbin thread should not be over-wound.
Standard diameter of wound bobbin thread: 16.5 to 19.5 mm
Rotation of bobbin (counter-clockwise)
Passes through the groove Rotation of bobbin (counter-clockwise)
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4.3.4 Poor tightness of stitches Poor stitch tightness (1)
№ Cause Remedy
1 Unbalanced needle and bobbin threads
Unless the thread tension is controlled according to the sewing condition such as fabric, type of thread, stitch length, sewing speed, etc., it will cause of poor tightness of stitches.
Correct tension for straight stitches The needle and bobbin threads are intertwined in the center of the fabric.
Proper tension for zigzag stitches In zigzag sewing, the bobbin thread is intertwined with the needle thread on the wrong side of the fabric about 2/3 the zigzag width.
1) Check if bobbin thread tension is appropriate. Standard bobbin thread tension for
horizontal full rotary hook: Between 12 g and 15 g with size 50 King
brand polyester thread (computerized sewing machines)
Standard bobbin thread tension for
oscillating hook: Between 30 g and 50 g with soft cotton
thread Note: Best sewing results can be obtained
on very thin fabrics with tension at 30 g (minimum).
Standard bobbin thread tension for high-speed straight stitch sewing machines (1600P series models): 20 ± 5 g with size 50 soft cotton thread
2) Check if needle thread tension is appropriate.
For best sewing results adjust the needle thread tension after adjusting the bobbin thread tension.
2 Incorrect needle thread and/or bobbin thread
Unless the needle thread and/or bobbin thread are threaded properly, it will cause poor thread tension and best sewing results cannot be obtained.
1) Rethread the needle thread and/or bobbin thread as shown in the instruction book.
3 Uneven drawing of needle thread
If the needle thread is caught in thread guide, etc., unusual tension will be applied to the needle thread, resulting in poor or uneven stitch tightness.
1) Check whether the needle thread can be smoothly pulled out from the spool.
Proper thread delivery from a spool
When it is not smooth: 2) Check if the pre-tension is functioning
properly 3) Check if there any scratches on the thread
path. 4 Uneven drawing of bobbin thread
If the bobbin thread cannot be drawn from the bobbin smoothly, it will cause poor stitch tightness.
1) Check if the direction the bobbin is inserted is correct (should be counter-clockwise).
2) Check if the amount of bobbin thread wound
is appropriate and winding is parallel. Standard diameter of wound bobbin thread:
16.5 to 19.5 mm
Center of fabric
Needle thread
Bobbin thread
Bobbin thread
Needle thread
Needle thread
2/3 of zigzag width
The end of the thread should come out from the bottomtoward the sewist (except for extremely rare threads thatdeliver from the opposite direction).
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Poor stitch tightness (2)
№ Cause Measure
5 Slackness in needle and bobbin thread at the start of sewing
If the needle and bobbin threads are not held firmly under the foot, there will be poor stitch tightness.
1) Before starting to sew, draw the both threads about 10 cm to the back under the presser foot
2) For presser feet that have groove(s) (i.e.
buttonhole foot, satin stitch foot) draw both threads to the left before starting to sew.
6 Improperly functioning check spring
If a check spring does not have proper spring pressure and does not function smoothly, it will cause poor stitch tightness.
1) Check whether the check spring functions smoothly in the operation range without interfering with the other parts.
2) Standard check-spring pressure and strokes:
Pressure: about 15 at maximum operation Strokes: within limit of operation range
(varies for each model; see users manual) at maximum operation
7 Irregular functioning of thread tension
unit
When the operation of the tension release mechanism is poor, and the tension of the thread tension unit does not function properly, it causes poor stitch tightness.
1) Check if the tension discs function properly when the presser foot is lowered.
2) Check if tension is set properly
Standard tension settings in horizontal full rotary hook sewing machines:
Dial at 4 70 – 85 g Dial at 0 15 g or less Dial at 9 180 g or more
(with King brand size 50 polyester thread)
(Tension may vary slightly depending on model)
8 Using inappropriate presser foot
If there is no groove for the thread path on the reverse side of the foot or a small presser foot is used, it will cause poor stitch tightness.
1) Check whether the presser foot specified in the instruction book is used.
2) There are grooves for thread path for straight
stitches at L, M and R needle positions on the reverse side of the presser foot designed by Janome. The grooves make proper tightness of stitches.
9 Using inferior thread
Since inferior thread has uneven thickness and low quality surface finish, it will cause poor stitch tightness.
1) In order to obtain proper thread tension and beautiful seam, we recommend using a good quality of thread.
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4.3.5 Puckering
Needle thread
Puckering (1) № Cause Remedy
1 Having tension too tight If thin fabric is sewn with overly strong
thread tension, it will cause the fabric to pucker.
Seam with strong Seam with strong needle thread tension bobbin thread tension
1) Adjust the upper thread tension so that both threads intertwine in the center of the fabric thickness.
2) In order to minimize fabric puckering, upper
thread tension may be made slightly weaker than normal.
Seam with weaker needle thread te
3) Check whether the bobbin thread ten
overly tight. 2 Incorrectly threaded needle thread
If the needle thread is threaded incorrectly and not delivered smoothly, it will cause the fabric to pucker.
1) Rethread the needle thread as showinstruction book.
3 Sewing very fine fabrics with long stitches
Seams sewn with long stitches consume more thread than short stitches. As a result, the thread is pulled tighter by the thread take up lever and the feed dog and causes the fabric to pucker.
1) It is better to set the thread tension aas possible when sewing very fine f
2) We recommend sewing with a slight
stitch length (2 - 2.5 mm). 3) Place a sheet of paper under the fab
sewing.
4) In the case of high speed straight stitsewing machines, professional usersa technique where the fabric and threheld together and pulled in the sewindirection while sewing.
4 Using thread that is too thick for the fabric
When thin fabric is sewn with thick thread, it becomes necessary to tighten the thread tension in order to obtain a good stitch. As a result, the fabric puckers.
1) Use thin thread when sewing thin fa
Type of fabric Thickness othread
Thin fabric #80 - #90
5 Using a needle that is too thick 1) When a thick needle penetrates the
fabric, the threads of the fabric will be pushed out of shape and the fabric will wrinkle.
2) As the needle moves up and down, it will pull the fabric with it and cause the fabric to wrinkle.
1) Use a thin needle when sewing thin
Wrinkling of the fabric when a thick neused.
Needle thread Needle thread
Bobbin thread
Bobbin th
70% Bobbinthread
Fabric puckers.
Needle
Fabric thpushed
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30%
nsion
sion is
n in the
s weak abric.
ly shorter
ric when
ch employ ads are g
bric.
f
fabric.
edle is
read
read is out
Puckering (2)
№ Cause Remedy
6 Using a needle plate or presser foot with a hole that is too large The fabric around the needle moves up and down according to the up/down movement of the needle and causes the fabric to pucker.
1) In the case of high speed straight sewing machines, use the needle plate with a 1.4 mm hole when sewing thin fabrics,. Note: The hole of the standard needle plate has a diameter of 1.8 mm.
2) Use the thin fabric presser foot which has a
smaller needle hole (diameter of 1.4 mm).
7 Having the foot pressure too strong
If the foot pressure is too strong, there will be slippage of the upper and lower fabric layers fabric, and it will cause puckering.
Puckering caused by slippage
1) When sewing thin fabrics, reduce the foot pressure until poor feeding does not occur.
2) When using a sewing machine with variable
foot pressure, the dial should be set to 2. 3) Check that there are no scratches on the
reverse side of the presser foot.
8 Having the feed dog height too high
If the feed dog is too high, since the lower layer will feed better than the upper layer, a variation in feed will occur and cause puckering.
1) Check whether the feed dog height is appropriate.
2) Standard feed dog heights: Household sewing machines (computer): 0.8
- 0.9 mm High speed straight stitch sewing machines:
0.8 - 1.0 mm 2) With high speed straight stitch sewing
machines, if the thin fabric needle plate (0.3 mm thicker than the standard needle plate) is used, feed dog height is reduced to 0.6 mm.
9 Leaning feed dog
If the front side of the feed dog is higher, a fabric will be pushed in more while sewing and cause puckering.
1) Make sure that the feed dog is parallel with the needle plate at the highest feed dog position.
2) In the case of the high speed straight stitch
sewing machine, the back of the feed dog should be about 0.03 mm higher than the front so that the fabric is correctly pulled while sewing in order to prevent puckering.
10 Failing to use the specified foot If the fabric is not fed together with the seam while being held by both the feed dog and presser foot, it will cause the fabric to pucker. If the thread path groove of the presser foot is large as with the satin stitch foot, it will be pulled too much when pulling up the needle thread, and will cause puckering.
1) Make sure to use the foot specified. 2) In the case of straight stitch sewing, it is
recommended that the presser foot for straight stitch be used.
Starting point Ending point Upper layer
Lower layer
Seam
Feed variance
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4.3.6 Poor fabric feeding Poor fabric feeding (1)
№ Cause Remedy
1 Insufficient foot pressure 1) If foot pressure is insufficient, since there
will not be enough friction between the feed dog and fabric, the fabric will slide and cause poor fabric feeding.
1) In the case of sewing machines with variable foot pressure, the dial should be set at 3 (max).
2) Feeding will improve if the sewing speed is
lowered. 3) Since sewing layers of thick fabric requires
more feeding power; not having sufficient foot pressure will cause poor fabric feeding.
2 Having the feed dog height too low The power of the fabric feed weakens the lower the feed dog height is set and will cause poor fabric feeding.
1) Make sure that the feed dog height is appropriate.
2) Standard feed dog heights: Household sewing machines (computer): 0.8
- 0.9 mm High speed straight stitch sewing machines:
0.8 - 1.0 mm 3) For machines with variable feed-dog height,
check if the feed dog height is set for thin fabric.
3 Incorrect timing of feed and feed lifting
The feed dog must remain parallel with the needle plate at all times. If the front or back sinks earlier, feed efficiency drops and causes poor fabric feeding.
1) Make sure that the ends of the feed dog teeth are parallel to the needle plate as they sink into the needle plate.
Note: It is very important that this is checked
whenever there is adjustment to the phase, such as when the needle bar displacement is adjusted.
Feed dog parallel to the needle plate (Both ends of the feed dog sink at the same time) The front sinks first
The back sinks first
4 Sewing over variable thicknesses When sewing over variable thicknesses, the presser foot is unable to climb over the thicker portions and causes poor feeding.
1) Check if the foot pressure is sufficient. 2) Check if the feed dog height is appropriate. 3) Check if the angle of the presser foot
movement is too small. 4) Lower the sewing speed and sew while
pulling the fabric in the direction of feeding especially when there is a significant difference in thickness.
Surface of needle plate
Surface of needle plate
Surface of needle plate
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Poor fabric feeding (2)
№ Cause Measure
５ Sewing hard to feed fabrics If the surface friction of a fabric is large and the bottom of the presser foot does not slide well, it will cause poor fabric feeding.
1) When sewing quilt sandwiches, sew using the even feed foot.
2) When sewing fabric which is hard to slide
such as vinyl or leather, sew using the ultra-glide foot.
６ Sewing stiff fabrics Since the bite of the feed dog is bad on a hard fabric, it will be the cause of poor fabric feeding.
1) Check if the tooth points of the feed dog have worn out since it influences the grip of the feed dog.
Note: If the tooth points of the feed dog are worn out, replace the feed dog.
2) Check whether foot pressure is weak. 3) Check if the feed dog height is appropriate. 4) Lower the sewing speed.
７ Sewing stretch stitches Although the feed dog of a sew tooth shape has good feeding efficiency, when sewing a reverse stitch like a stretch stitch, it causes poor fabric feedings.
1) Pyramid-shaped feed dog teeth are better suited for this type of stitch.
Note Since numerical values vary depending on model, refer to the servicing manual for standard values.
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4.3.7 Hitched stitches Hitched stitch (1)
№ Cause Remedy
1 Incorrectly threaded needle thread
If sewn without being properly threaded through the needle bar thread guide, a the force of the thread will become large at the upper part of the needle, making the needle thread loop around the needle from the right-side and causing the stitch to become hitched.
Normal Hitched stitch
1) Rethread the machine as shown in the instruction book. Be careful not to forget to thread through the needle bar thread guide when changing the needle or thread.
Normal stitches
Hitched stitches
2 Reverse sewing During reverse sewing, since the thread is sent forward after being sewn, the needle thread may loop around the needle from the right-side and cause the stitch to become hitched. Forward sewing Reverse sewing
1) Use the presser foot with the guide for hitched stitch prevention.
Hitched stitch preventing structure
Ordinary foot With guide
3 Weak bobbin thread tension and tangled bobbin thread If the delivery of the bobbin thread is tangled when the bobbin thread is brought to the right of the needle, the tip of hook will catch the loop and cause of hitch stitch. Normal Hitched stitch
1) Make sure that the bobbin thread tension is appropriate.
Note: Refer to No. 3 on page 32 for the correct bobbin thread tension.
2) Check if the set position of the bobbin holder/bobbin case is correct.
Normal stitches
Hitched stitches
Bobbin thread
Needle thread
Bobbin thread Needle thread
Needle thread turns to the front from the right
Twisted Fabric Bobbin thread
Needle thread Needle thread
Fabric
Guide
Hole for needle
Bobbin thread
Bobbin thread
Bobbin thread passes in front of the needle.
Bobbin thread passes behind the needle
Bobbin thread
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Needle thread
Needle threadBobbin thread
Needle threadNeedle thread
4.3.8 Broken or bent needles Broken or bent needles (1)
№ Cause Remedy 1 Incorrect needle insertion
If the needle is not attached properly, it may come into contact with the presser foot or the needle plate and cause the needle to bend or break.
1) Check if the needle is attached with the correct orientation. Note: Refer to No. 5 on page 26.
2) Check if the needle is fastened securely.
2 Bent or dulled needles If the needle becomes bent or dulled, it may cause the needle to break.
1) Refer to No. 6 on page 27.
3 Using a needle that is too thin for the fabric If the appropriate size of needle is not used when sewing thick stiff fabrics, the needle may bend or break.
1) Check whether the correct combination is being used as shown in the following table.
Fabric thickness
Type of fabric Needle size
Thin Gauze, voile etc.
#9 - #11
Ordinary
Broadcloth, seersucker, etc.
#11 - #14
Thick Quilting, denim, etc.
#14 - #16
Extra thick 6 to 14 layers of denim, leather, etc.
DB x 1 #16 - #18
4 Pulling fabric while sewing
If the fabric is pulled too strongly, the needle thread will bend the needle and may cause it to stay bent or even break.
1) When sewing, gently guide the fabric and without pulling it.
2) Do not pull the fabric while the needle is in
the fabric.
5 Changing needle position while the needle is in the fabric. If the zigzag width or needle position is changed while the needle is in the fabric, it may cause the needle to bend or break.
1) When using a mechanical sewing machine, be sure that the needle is always raised when changing the needle position, stitch or zigzag width.
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Chapter 5: Household overlock sewing machines
The household overlock sewing machine is the general name used for domestic sewing machines capable of making chain stitch types of seams. Stitches consist of needle and looper threads, can be made with 1, 2 or 3 needles and include the following different types of stitches: single chain-stitch, double chain-stitch, over-edge stitch, compound stitch, flat seam stitch, etc.
5.1 Introduction to the overlock mechanism
The following are diagrams of the mechanism in Janome’s overlock sewing machines.
* Presser bar With the presser foot attached
to the lower end, and the presser foot spring attached to the upper end, the presser bar applies foot pressure to the presser foot.
* Needle bar A needle thread loop is
formed by the needle penetrating the fabric. The needle catches the upper looper thread, which comes out of looper eye.
* Upper looper The upper looper catches the
lower looper thread, which comes out of the lower looper eye, underneath the fabric. It carries the upper looper thread to the left and passes the thread to the needle.
* Lower looper The lower looper catches the
needle thread loop underneath the fabric, and passes the lower looper thread to the upper looper.
Lower looper
Upper looper
Feed dogs
Needle bar
Presser bar
1) Needle bar mecha
Presser bar lifter
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Overall Mechanism
2) Upper & lower looper mechanism
Hand wheel
Differential feed dial
Stitch length dial
nism
* Upper knife mechanism Before overlocking the fabric edge,
the upper knife cuts the fabric edge to an even width.
3) Presser bar lifer & Tension release mechanism
Tension unit * Main feed dog Located behind the presser foot, this
feed dog feeds the fabric that has been sewn.
Tension dial
The main feed dog serves as the main control of the amount of feed)
* Sub feed dog Located in the front of the needle, this
feed dog pushes the fabric toward the needle. The amount the fabric is sent can be adjusted in correlation to the amount of feed of the main feed dog.
4) Upper knife driving mechanism
5) Feed adjusting mechanism
Main & sub feeding mechanism
* Differential feed mechanism This mechanism allows stretch
sewing or gathering through the movement of the sub feed dog.
* Feed adjusting mechanism This mechanism sets the amount of
motion of the main and sub feed dog, and adjusts stitch length.
Sub feed dog
* Thread tension dial This dial regulates the tension
balance between the needle, upper looper, and lower looper threads. Unlike zigzag sewing machines, overlock sewing machines are unable to make a variety of stitch patterns. Stitch variations are made instead by changing the tension balance between the 3 (or 4) threads.
Main feed dog
6) Differential feed mechanism
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5.2 Guide to overlock stitches
5.2.1 Description and formation of basic overlock stitches 1) Single chain stitch Description One thread interlinks with itself in the shape
of a chain under the fabric, and has the stitch formation like that of knitting.
Structurally, if the end of the interlinked stitch is removed, the seam will continue unraveling.
Stitch formation
Needle Step A The needle thread is loosened as the needle moves slightly from the lowest point, and the looper catches the looped needle thread. When the needle comes down, the needle enters into the loop of the needle thread, which is extended by the looper.
Looper
Step B The needle comes out of the fabric and the fabric is fed. The looper rotates, and it releases the thread caught previously while drawing the needle thread. The needle bar continues to move up and the thread take up lever pulls up the needle thread. Step C The looper continues its rotation drawing the thread to the central part of the looper, and the thread fastens the thread that was previously removed.
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Step D The fabric feeding finishes, a stitch is formed and the needle penetrates the fabric again. The process returns to Step A and continues.
2) Double chain stitch Description The needle thread (1) and the looper thread
(a) intertwine in the shape of a chain under the fabric. The stitch formation resembles knitting. The seam looks similar to the lock stitch on the right side of the fabric. Since the needle thread as well as the looper thread can be supplied continuously, it can be sewn continuously for a long time.
１
ａ
As this stitch formation has a lot of give, it is widely used for the stretch fabrics and in high-stress areas.
The weak point is that this stitch comes loose easily.
The looper picks up the needle thread.
Needle
Stitch formation Step A The needle thread is released from the looper, and tightened. The looper then picks up the needle thread as the needle moves up slightly from the lowest point. Step B The needle continues to move up, and the looper thread is released from the needle. The looper thread moves forward through the loop of the needle thread.
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Step C The fabric is fed when the needle is at its highest point and the looper is at the rightmost position, and the final needle thread fastening is performed.
The needle picks up the looper thread
Needle
Step D The needle moves down, and the tip of the needle picks up the looper thread. Note that the looper is moving in an ellipse. The process then returns to Step A and continues.
3) Over-edge stitch Description Most over-edge stitches are formed with 3 threads (needle thread (1), upper looper thread (a) and lower looper thread (b)) intertwined at the edge of the fabric like a hemstitch.
１
a b Over-edge stitching is classified as a chain
stitch, and since the stitch itself can be stretched with the fabric, it is commonly used on fabrics that have a great deal of stretch such as knits.
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Stitch formation Step A The lower looper picks up the needle thread loop. Step B The upper looper thread is cleared from the needle and the upper looper picks up the lower looper thread. Step C The fabric is fed. Step D The tip of the needle picks up the upper looper thread.
Cleared
Needle thread
Lower looper thread
Upper looper thread
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Cleared
Cleared
Step E The lower looper thread held by the upper looper is released. The needle thread held by the lower looper is then released. Step F The needle, while moving toward its lowest position, fastens the needle thread onto the previous stitch. The process then proceeds returning to Step A.
5.2.2 Composition and use of each stitch (and applicable Janome machine) 1) 1 needle – 2 thread overlock * Edging and rolled hems General overlock machines (Requires spreader attachment) 2) 1 needle – 3 thread overlock * Edging and rolled hems General overlock machines 3) 2 needle – 4 thread overlock * 2-seam overlocking General overlock machines 4) 2 needle – 5 thread overlock * Interlocking (double chain + over-edge) CompuLock (computerized serger) 5) 2 needle double chain stitch * Cover stitching CoverPro 900CP (2 thread cover stitch machine) 6) 3 needle double chain stitch * Triple cover stitching CoverPro 1000CP (2 or 3 thread cover stitch
machine)
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Chapter 6: Glossary of household sewing machine terminology 6.1 Stitch and sewing method terminology 6.1.1 Overall terms for stitch structure No Term Definition Stitch structure 1 Lock stitch A stitch formed through the intertwining of a
needle thread and a bobbin thread.
2 Chain stitch A stitch formed through the intertwining of a single thread in the shape of a chain; also called a single chain stitch. In addition, on the right side of the fabric, it looks the same as a lock stitch, but on the wrong side is chain-like.
6.1.2 Terms for main stitch patterns No Term Definition Stitch shape 1 Straight
stitch The stitch pattern sewn in a continuous straight line along the direction of movement.
2 Zigzag stitch
The stitch pattern sewn alternating one stitch right and one stitch left.
3 Multiple zigzag stitch
The stitch pattern sewn in a zigzag with continuous individual stitches from left to right and right to left.
4 Satin stitch The stitch pattern sewn in a zigzag with very little feed so as to have the stitches lined up horizontally; also called adhesion stitch or mall stitch.
5 Multiple decorative stitch
General term for stitch patterns formed from a dotted line stitch where the directions of the individual stitches are changed in a periodic fashion.
6 Decorative zigzag stitch
General term for stitch patterns formed from a zigzag stitch where the width is changed in a periodic fashion, or a combination of such a pattern and a dotted line stitch.
7 Decorative stretch zigzag stitch
General term for automated stitch patterns formed from a combination of zigzag stitches, dotted line stitches, etc. where the direction and size are changed in a periodic fashion.
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No Term Definition Stitch shape 8 Twin needle
sewing General term for stitch patterns sewn using 2 needles or a twin needle.
9 Blind stitch The stitch pattern formed from several straight stitches followed by 1 or 2 zigzag stitches.
10 Triple stitch
The stitch pattern where each straight or zigzag stitch is sewn forward, reverse and then forward again before proceeding to the next stitch.
11 Scallop stitch
A stitch pattern formed from zigzag or dotted stitches sewn in an arc.
12 Cycle stitch General term for stitch patterns completed in one cycle such as buttonholes (1), eyelets (2), and monograms (3).
6.1.3 Terms for main sewing techniques
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No Term Definition Illustration 1 Reverse
stitch To sew using the reverse feed device. Used for: (1) Locking a straight stitch (2) Attaching interfacing by repeating forward
and reverse stitches. (3) Attaching belt loops, cords, etc. firmly by
repeating forward and reverse stitches
2 Basting An easy to remove seam used to stop
slippage of layers of fabric, or as a marking to sew precisely Basting techniques: (1) Sew with the needle and bobbin thread
tensions unbalanced (2) Use a chain stitch (3) Sew with very long stitch length
3 Stretch stitching
A method of sewing used on stretch fabrics to prevent breaking or loosening of the seam when the fabric is stretched. Applicable stitches: chain stitch, multiple zigzag stitch, triple stitch and twin needle stitch.
No Term Definition Illustration 4 Zipper
application To attach a zipper using a zipper foot.
5 Cording To attach embroidery thread, yarn, cords, etc. to fabric using a cording foot; also called cord embroidery.
6 Appliqué To zigzag sew the edge of a small piece of fabric, felt, leather, etc. cut in various shapes in order to attach it to a larger piece of fabric.
7 Rolled hemming
To sew the triple folded edge of a fabric using a rolled hemming foot.
8 Plain seam Aligning two fabrics with the right sides
together and sewing with the wrong side up.
9 Topstitched seam
A method of joining fabrics by aligning the right sides together, opening up the seam allowance, and sewing each side to the wrong side of fabric.
10 Abutted
seam A method of joining fabrics. The ends of the two fabrics are aligned, pinned to an underlay fabric and sewn with a zigzag or multiple zigzag stitch.
11 Fagoting A decorative method of joining fabrics. The ends of two fabrics are aligned parallel a short distance apart and sewn with a decorative zigzag or decorative stretch zigzag stitch.
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No Term Definition Illustration 12 Shell
tucking A decorative hem for thin fabrics that resembles a row of shells made by folding along the bias and, using a blind stitch, sewing so that the zigzag drops over the left edge of the fabric.
13 Quilting A method of both joining fabrics and decoration; used to fix batting between layers of fabric
14 Overcasting To sew the edge of fabrics with a simple zigzag, dotted line zigzag or decorative zigzag stitch in order to prevent the fabric from fraying.
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6.2 Terms for household sewing problems No Term Definition Illustration 1 Thread break
(Needle thread break) (Bobbin thread break)
Breakage of the thread when stress is applied to the seam.
2 Skipped stitch Portions where the sewing thread fails to intertwine occasionally as well as portions where it cannot be sewn at all.
3 Uneven stitch
The development of areas where the threads intertwine irregularly on the top and/or the underside of the fabric although sewn under constant thread tension.
4 Looping (Poor thread tightness)
The sudden formation of large or small loops from where the threads interlock on either the top or underside of the fabric
5 Towel loops (Poor thread tightness)
The continuous formation of loops on the underside of the fabric
6 Loose stitches (Poor thread tightness)
Since the sewing thread tension is insufficient, a space develops between the two fabrics.
7 Pulled or rippled fabric
Pulling of the fabric around the stitching caused by the thread tension being too tight or the threads of the fabric being too weak
8 Layer slippage
Sliding of upper and lower layer of fabrics in the direction of feed
Underside
Broken needle thread Seam Top
Broken bobbin thread
Seam
Skipped stitch
Seam Top
Underside
Seam Top loopi
Underside loopin
Underside
Needle thre
Fabric rippling
Starting point
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Skipped stitches
Uneven stitches (lower)Uneven stitch (upper)
ng
Topg
Top
Towel loopsFabricad
Bobbin thread
Ending point
Top of fabric
Slippage
UndersideSeam
Gap
No Term Definition Illustration 9 Seam
puckering
Wrinkles, pulling, or slippage of the fabric around the stitching
10 Blocked stitches
Some sort of resistance is imparted to object being sewn causing the pitch to become irregular
11 Pitch error
An irregular change in the length of the stitches caused by a change of feeding power, fabric slippage, etc.
12 Deviated stitching
Stitching that is not straight; stitches falling outside of a straight line.
13 Askewed stitching
Instead of forming a continuous straight line, the thread shifts between the start and finish of each stitch
14 Perfect stitches
When the needle thread and bobbin thread interlock without any twisting
15 Hitched stitches
When the needle thread is twisted where it interlocks with the bobbin thread
16 Unraveled stitches
When the needle and bobbin threads become unlocked; also referred to as jumping
* The fabric is pulled and puckering appears.
Puckering (wavy)
Underside
Top Seam
Blocked stitches
Blocked stitches
Fabric
Stitch
Uneven feeding
Deviated stitching
Fabric
Seam Fabric
Needle thread
Bobbin thread
Unraveled stitch
Unraveled stitch
Twisted
Bobbin thread
Needle thread
Fabric
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Fabric
No Term Definition Illustration 17 Frayed
threads
Where several single fibers of the sewing thread are broken in the middle of sewing
18 Fabric thread breakage
Cutting of the thread of the fabric by the sewing machine needle at the time of sewing
19 Feed dog marks
Marks made by the feed dog made as the fabric is fed
20 Chaining off
Forming nodal points without fabric
© 2005 Ja
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Needle thread
no
Bobbin thread
m
c
me Sewing Mac
Frayed thread
Breakage of fabric thread FabricSea
Wrong side of the fabri Feed dog markshin
Chaining off
Needle threadBobbin thread
e Co, Ltd., Tokyo, Japan
