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Maharashtra HSC NSQF Specialised Sewing Machine Operator study materials
Maharashtra HSC NSQF Specialised Sewing Machine Operator study resources

Maharashtra HSC NSQF Specialised Sewing Machine Operator practice questions

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Question 1Occupational Safety, Health and Working Environment in Garment Production

On a single-needle lockstitch machine in a garment factory, which practice best protects the operator's fingers while guiding fabric close to the needle?

  1. Use a finger guard and keep fingers to the side of the needle, not in front of it Correct answer.
  2. Remove the finger guard for better visibility of the needle point
  3. Guide the fabric directly in line with the needle so the stitch line stays straight
  4. Increase machine speed so the fabric passes the needle quickly

Explanation

A finger guard is a physical barrier that keeps fingers from entering the needle path, and guiding fabric from the side rather than in front of the needle reduces the chance of needle-stick injury. Speed and visibility concerns never justify removing a guard.

Question 2Occupational Safety, Health and Working Environment in Garment Production

What is the main purpose of the eye guard fitted over the needle and presser foot area of an industrial sewing machine?

  1. To keep the bobbin thread tension constant while sewing
  2. To reduce motor noise during high-speed operation
  3. To shield the operator's eyes from a broken needle or flying needle fragment Correct answer.
  4. To hold the fabric flat against the feed dog during stitching

Explanation

The eye guard is a transparent shield positioned between the needle zone and the operator's face. Its function is to stop broken needle pieces or debris from striking the eyes. Fabric handling and tension control are functions of the presser foot, feed dog and tension discs.

Question 3Occupational Safety, Health and Working Environment in Garment Production

In a garment production line, why should the power table or socket for a sewing machine be switched off and locked out before the needle plate is removed for cleaning?

  1. To reset the stitch length setting to its default value
  2. To discharge static electricity from the fabric
  3. To allow the machine oil to settle before maintenance
  4. To prevent accidental start-up of the motor while hands are in the needle and feed mechanism Correct answer.

Explanation

Lockout and tagout isolate the energy source so the machine cannot be started by another worker or by a foot pedal while hands are inside the needle and feed area. Cleaning tasks such as removing lint under the needle plate place hands in a pinch and puncture zone.

Question 4Occupational Safety, Health and Working Environment in Garment Production

Which posture guidance applies to an operator seated at a sewing machine for a full shift?

  1. Adjust the chair height so elbows are near a right angle and feet rest flat on the pedal or floor Correct answer.
  2. Lean forward with the neck bent so the needle area is close to the eyes
  3. Keep the chair as low as possible so the knees are above hip level
  4. Sit at the front edge of the seat with the back unsupported to stay alert

Explanation

Correct workstation adjustment keeps the forearms roughly horizontal and the feet supported, which reduces strain on the shoulders, wrists and lower back during long shifts. Leaning forward or sitting without back support increases musculoskeletal stress.

Question 5Occupational Safety, Health and Working Environment in Garment Production

A cutter using a straight-knife cutting machine must wear which combination of personal protective equipment for the task?

  1. No gloves, because gloves reduce grip on the fabric
  2. Disposable plastic gloves and a hairnet only
  3. Cut-resistant glove on the fabric-guiding hand and safety footwear Correct answer.
  4. Cotton hand gloves on both hands and a dust mask

Explanation

The straight knife has an exposed reciprocating blade, so a cut-resistant glove protects the hand that guides the fabric, while safety footwear protects the feet from a falling knife or dropped weights. Loose cotton gloves offer little cut resistance and can be caught by the blade.

Question 6Occupational Safety, Health and Working Environment in Garment Production

Which action is the correct first response when a worker's finger is punctured by a sewing machine needle?

  1. Stop the machine, encourage bleeding, wash the wound and report for first aid and tetanus review Correct answer.
  2. Apply a dry cloth and resume work once the bleeding stops
  3. Wrap the finger tightly and finish the bundle before reporting
  4. Continue sewing and clean the wound with machine oil at the end of the shift

Explanation

A needle puncture is a contaminated wound, so the machine must be stopped and the wound cleaned and assessed by a first-aider, including checking tetanus cover. Delaying treatment or using machine oil on the wound risks infection.

Question 7Occupational Safety, Health and Working Environment in Garment Production

Why is local exhaust ventilation fitted at the overlock machine and at the fabric cutting table?

  1. To blow fabric dust away from the operator's face
  2. To maintain humidity in the production hall
  3. To cool the motor and prevent it from overheating
  4. To capture lint and fabric dust near the source before they are inhaled Correct answer.

Explanation

Local exhaust ventilation extracts airborne lint and fabric dust at the point of generation, preventing them from dispersing into the breathing zone. Blowing dust with a fan only moves it into the air where others can inhale it.

Question 8Occupational Safety, Health and Working Environment in Garment Production

A worker in the finishing section develops itching and redness on the forearms after handling garments treated with a finishing chemical. What is the most appropriate immediate action?

  1. Ignore the reaction because skin irritation is normal in garment finishing
  2. Apply a strong solvent to the skin to remove the chemical quickly
  3. Stop handling the material, wash the skin with water and mild soap, and report the reaction to the supervisor Correct answer.
  4. Cover the arms with a tight bandage and continue working

Explanation

Skin contact with a finishing chemical can cause contact dermatitis, so the affected area should be washed promptly with water and mild soap and the incident reported so the exposure can be investigated. Solvents and occlusive bandages can worsen the reaction.

Question 9Occupational Safety, Health and Working Environment in Garment Production

Before using a spot-removal chemical on a garment, where should the operator find the handling precautions, PPE requirements and first-aid measures?

  1. On the product label and the safety data sheet held at the workstation Correct answer.
  2. In the employee attendance register
  3. In the machine maintenance log book
  4. In the production target chart for the day

Explanation

Hazard information for a chemical is given on the container label and in the safety data sheet, which covers hazards, safe handling, PPE and first aid. Production charts and log books do not contain chemical hazard data.

Question 10Occupational Safety, Health and Working Environment in Garment Production

What is the correct way to store needles, scissors and trimming blades at the end of a shift in the sewing section?

  1. In a closed container or designated holder with the points shielded Correct answer.
  2. On the floor beside the machine
  3. Loose on the machine table so they are easy to find next shift
  4. Tucked into the fabric bundle being sewn

Explanation

Sharp tools left loose are a common cause of cuts and of stray metal reaching the fabric, which can damage machines and injure wearers. Storing them in a closed container or holder with points shielded removes the hazard.

Question 11Occupational Safety, Health and Working Environment in Garment Production

Why must a broken needle be accounted for completely before sewing continues on that machine?

  1. The machine cannot form a stitch until all fragments are collected
  2. The fragment count is required for the daily production report
  3. A missing needle fragment can remain in the fabric and injure the wearer or damage downstream machines Correct answer.
  4. Needle fragments affect the thread tension setting

Explanation

Broken needle pieces can embed in the sewn garment or fall into the machine, creating a risk of injury to the wearer and of damage to cutters and presses downstream. Factories therefore use needle control procedures to recover all fragments.

Question 12Occupational Safety, Health and Working Environment in Garment Production

Which of the following is the correct manual handling technique for lifting a bundle of cut fabric from a trolley?

  1. Bend the knees, keep the load close to the body and lift with the leg muscles Correct answer.
  2. Hold the bundle at arm's length to keep it away from the uniform
  3. Lift quickly with a jerk to overcome the weight
  4. Bend at the waist with straight legs and twist to place the bundle on the table

Explanation

Bending the knees and keeping the load close reduces the lever arm on the lower back, and using the leg muscles distributes the effort to stronger muscle groups. Twisting or jerking while lifting sharply increases the risk of back injury.

Question 13Occupational Safety, Health and Working Environment in Garment Production

A worker notices a frayed power cable on a sewing machine with exposed inner wires. What is the correct action?

  1. Continue working but wear rubber-soled footwear
  2. Shift the machine slightly so the cable is not touched during work
  3. Stop using the machine, isolate it and report the defect for repair by a qualified electrician Correct answer.
  4. Wrap the exposed section with fabric tape and continue sewing

Explanation

A frayed cable with exposed conductors is an electrical shock and fire hazard, so the machine must be taken out of use and the defect reported for repair by a competent person. Taping or repositioning leaves the hazard in place.

Question 14Occupational Safety, Health and Working Environment in Garment Production

Which condition indicates that the emergency stop device on a sewing machine is functioning correctly?

  1. Pressing it stops the machine immediately and the machine cannot restart until the device is reset Correct answer.
  2. Pressing it stops the machine but the foot pedal can still start it
  3. Pressing it slows the machine gradually over several seconds
  4. Pressing it sounds an alarm while the machine keeps running

Explanation

An emergency stop must remove power quickly and latch so the machine cannot restart until it is deliberately reset. Gradual slowing, restart from the pedal, or an alarm without stopping does not meet the purpose of an emergency stop.

Question 15Occupational Safety, Health and Working Environment in Garment Production

A worker is exposed to noise from a bank of high-speed overlock machines throughout the shift. Which control measure is the most effective according to the hierarchy of controls?

  1. Issue earplugs to every worker on the line
  2. Rotate workers so each person spends less time near the machines
  3. Reduce noise at source through machine maintenance, damping and enclosure Correct answer.
  4. Display a noise hazard sign at the entrance

Explanation

The hierarchy of controls places engineering measures such as reducing noise at source, damping and enclosure above administrative controls and PPE. Earplugs and rotation are lower-order measures used when source control cannot reduce exposure sufficiently.

Question 16Occupational Safety, Health and Working Environment in Garment Production

Which set of conditions most accurately describes a confined space such as a dyeing or storage tank that a maintenance worker may need to enter?

  1. An open loading dock used for unloading fabric rolls
  2. A room with two doors and normal lighting used for fabric inspection
  3. Limited entry and exit, not designed for continuous occupancy, and capable of containing a hazardous atmosphere Correct answer.
  4. A large open production hall with several exits and continuous ventilation

Explanation

A confined space is defined by restricted entry and exit, unsuitability for continuous occupancy, and the potential for a hazardous atmosphere or other serious hazard. Open production areas and loading docks do not meet these criteria.

Question 17Occupational Safety, Health and Working Environment in Garment Production

During a fire evacuation from the stitching floor, what is the correct behaviour for the operator?

  1. Leave the machine running, use the marked exit route and assemble at the designated point for roll call Correct answer.
  2. Wait near the machine until the supervisor confirms the alarm is genuine
  3. Collect personal belongings from the locker before leaving the floor
  4. Use the nearest lift to reach the ground floor quickly

Explanation

Evacuation requires leaving the work area promptly by the marked route and reporting at the assembly point so that a roll call can confirm everyone is out. Lifts must not be used during a fire and delays put lives at risk.

Question 18Occupational Safety, Health and Working Environment in Garment Production

In a garment factory using solvent-based spot removers, which fire precaution is essential in the storage area?

  1. Store next to the boiler room so the chemicals stay warm
  2. Keep containers open so vapours do not build up inside them
  3. Store in closed containers away from ignition sources with suitable fire extinguishers and ventilation Correct answer.
  4. Store the chemicals in the same cabinet as the sewing machine lubricants without labelling

Explanation

Solvent-based spot removers give off flammable vapours, so they must be kept in closed containers away from heat and ignition sources, with ventilation and appropriate fire extinguishers nearby. Open containers and proximity to a boiler create a serious fire risk.

Question 19Occupational Safety, Health and Working Environment in Garment Production

Which practice correctly addresses the risk of slips and trips on a garment assembly line?

  1. Allow bundles to be stacked in the aisle when the table is full
  2. Clean the floor only at the end of the month
  3. Leave trailing machine cables across the walkway because they are visible
  4. Keep gangways clear, route cables overhead or in covers, and clean up thread and fabric scraps promptly Correct answer.

Explanation

Slips and trips on a production floor are controlled by keeping walkways clear, managing cables and removing thread and fabric waste before it accumulates. Storing bundles in aisles and leaving trailing cables create obstructions.

Question 20Occupational Safety, Health and Working Environment in Garment Production

What is the purpose of a pre-shift safety check of a sewing machine before production begins?

  1. To check the colour of the thread against the sample
  2. To confirm guards, needle condition, cables and stop devices are in safe working order before the machine is used Correct answer.
  3. To set the stitch pattern for the new style
  4. To record the operator's daily output target

Explanation

A pre-shift check identifies damaged guards, bent or blunt needles, damaged cables and faulty stop devices before the machine is used, so defects can be corrected before they cause injury. Output, stitch pattern and thread colour are production settings, not safety checks.

Question 21Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

In a single-needle lockstitch machine, which part pulls the thread from the spool and supplies it to the needle at a controlled rate?

  1. The bobbin winder
  2. The presser foot
  3. The feed dog
  4. The take-up lever Correct answer.

Explanation

The take-up lever rises and falls with the needle bar and meters thread to the needle while also pulling the stitch tight after the loop passes around the bobbin. It is the main thread-controlling element between the tension discs and the needle. The bobbin winder only fills bobbins, and the feed dog and presser foot move and hold fabric.

Question 22Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which needle system designation is the standard short shank needle used in most Indian domestic and light industrial single-needle lockstitch machines?

  1. 135x17
  2. DPx5
  3. UY128GAS
  4. DBx1 Correct answer.

Explanation

DBx1 is the short shank, flat side-to-back needle used in most domestic and light industrial single-needle lockstitch machines. DPx5 and 135x17 are longer industrial needles with a different shank, and UY128GAS is a coverstitch needle. Matching the needle system to the machine prevents needle bar and timing damage.

Question 23Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

A needle is marked '90/14'. What does the number 90 refer to?

  1. The metric needle size, i.e. blade diameter in hundredths of a millimetre Correct answer.
  2. The needle length in millimetres
  3. The recommended thread count
  4. The shank diameter in hundredths of an inch

Explanation

The metric (Nm) needle size expresses blade diameter in hundredths of a millimetre, so size 90 means a 0.90 mm blade. The second number, 14, is the equivalent Singer/imperial size. The size does not state needle length or thread count.

Question 24Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which thread is a filament synthetic thread with high strength and low shrinkage, commonly used for sewing synthetic fabrics and overlocking?

  1. Polyester filament Correct answer.
  2. Linen
  3. Mercerised cotton
  4. Wool

Explanation

Polyester filament thread is a continuous-filament synthetic with high tenacity, low shrinkage and good resistance to rot, making it suitable for synthetic fabrics and overlock seams. Mercerised cotton is a staple natural thread with more shrinkage, and linen and wool are natural fibres not used as general sewing filaments.

Question 25Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What is the primary function of the presser foot in an industrial lockstitch machine?

  1. To regulate the bobbin tension
  2. To guide the needle into the bobbin case
  3. To cut the thread after sewing
  4. To hold the fabric firmly against the feed dog during stitch formation Correct answer.

Explanation

The presser foot presses the fabric against the feed dog so that the teeth can grip and advance it one stitch length at a time. It also keeps the fabric steady while the needle forms the loop. Thread cutting, needle guidance and bobbin tension are handled by other parts.

Question 26Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which machine type uses two needle threads and two looper threads to form a stretch seam on knit garments?

  1. Overlock (serger) machine Correct answer.
  2. Buttonhole machine
  3. Single-needle lockstitch machine
  4. Blindstitch machine

Explanation

An overlock machine uses one or two needle threads together with one or two looper threads to encase the fabric edge and produce a stretchable seam. Lockstitch machines use a bobbin thread, blindstitch machines form a hidden stitch, and buttonhole machines make buttonholes. The overlock's loopers are what allow the seam to stretch with knits.

Question 27Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What is the purpose of the needle plate hole in a lockstitch machine?

  1. To allow the needle to pass through and the thread loop to be formed around the bobbin Correct answer.
  2. To hold the bobbin in place
  3. To adjust the stitch length
  4. To guide the fabric edge

Explanation

The needle plate hole lets the needle carry the thread below the fabric so a loop can be formed and picked up by the hook. A hole that is too large for the needle can let fabric be pushed down and cause skipped stitches. The bobbin is held in the bobbin case, and stitch length is set by the feed regulator.

Question 28Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which of these is a standard type of feed mechanism found on industrial lockstitch machines?

  1. Tension disc feed
  2. Rotary hook feed
  3. Drop feed Correct answer.
  4. Loop take-up feed

Explanation

Drop feed is the common feed type in which feed dogs rise through the needle plate to move the fabric. Other recognised feed types include needle feed, walking foot and puller feed. Rotary hook, take-up and tension disc are not feed mechanisms but parts of stitch formation.

Question 29Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

A tailor is sewing a medium-weight cotton shirting and the needle keeps bending and skipping stitches. Which change is the most appropriate first step?

  1. Fit a stronger needle of suitable size for the fabric and thread, and re-check timing Correct answer.
  2. Reduce presser foot pressure to zero
  3. Fit a finer needle and loosen the bobbin case
  4. Change to a polyester filament thread of a heavier ticket

Explanation

A bending needle usually indicates the needle is too fine for the fabric and thread, or that it is deflected by a timing or needle plate problem. Fitting a stronger needle of the correct size and checking hook timing addresses the likely cause. Loosening bobbin tension or reducing foot pressure does not correct a bent needle.

Question 30Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which condition most directly causes the needle thread to loop and pucker on the underside of a lockstitch seam?

  1. The presser foot pressure is too high
  2. The needle thread tension is too loose Correct answer.
  3. The stitch length is too short
  4. The bobbin case tension is too tight

Explanation

When needle thread tension is too loose, the needle thread is not pulled fully up through the fabric and forms loops or tangles on the underside. The correct balance is achieved by adjusting upper tension to suit the bobbin case tension. Tight bobbin tension pulls knots to the top, and foot pressure or stitch length affect feeding rather than knot position.

Question 31Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

For sewing a light chiffon fabric, which needle and thread combination is most suitable?

  1. Size 90/14 needle with ticket 20 cotton thread
  2. Size 100/16 needle with ticket 40 polyester thread
  3. Size 60/8 or 70/10 needle with a fine ticket 120 thread Correct answer.
  4. Size 110/18 needle with heavy nylon thread

Explanation

Fine, lightweight fabric needs a small needle and a fine thread so the needle does not leave visible holes or damage the weave. A 60/8 or 70/10 needle with a fine ticket 120 thread suits chiffon. Heavy needles and coarse threads would tear the fabric and produce puckered seams.

Question 32Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What is the function of the tension discs in a lockstitch machine?

  1. To guide the thread into the take-up lever
  2. To grip the needle thread and control its resistance as it feeds to the needle Correct answer.
  3. To hold the bobbin thread during bobbin winding
  4. To press the fabric against the feed dog

Explanation

The tension discs grip the needle thread between them, and the amount of pressure set by the tension dial controls how much resistance the thread meets. This resistance balances the bobbin case tension to place the stitch knot inside the fabric. Fabric holding is the presser foot's job, and bobbin winding uses a separate tension unit.

Question 33Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which needle point type is designed for knitted fabrics to push yarns aside rather than cut them?

  1. Leather point
  2. Sharp point
  3. Chisel point
  4. Ball point Correct answer.

Explanation

A ball point needle has a rounded tip that slips between knit loops and pushes yarns aside, reducing laddering and skipped stitches. Sharp points are for woven fabrics, leather points are for leather, and chisel points are used for heavy materials. Choosing the right point protects the knit structure.

Question 34Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What is the main reason for using a needle with a scarf (the short groove above the eye)?

  1. To hold the needle in the needle bar
  2. To strengthen the needle shank
  3. To reduce needle heat
  4. To allow the hook to pick up the thread loop reliably Correct answer.

Explanation

The scarf is a recess above the eye that lets the rotary hook pass close to the needle and catch the thread loop reliably. Without a proper scarf, the hook may miss the loop and cause skipped stitches. The shank holds the needle in the bar, and grooves help thread passage and heat reduction but are not the scarf's main purpose.

Question 35Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which thread numbering system indicates a finer thread by a higher number?

  1. Ply count
  2. Denier system
  3. Metric ticket (Nm) system Correct answer.
  4. Tex system

Explanation

In the metric ticket (Nm) system, a higher number means more metres per gram, so the thread is finer. Tex works the opposite way, with higher values indicating heavier threads. Denier is a filament weight system, and ply count describes the number of strands, not fineness.

Question 36Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What does the term 'seam allowance' refer to in garment construction on an industrial machine?

  1. The space between the tension discs
  2. The length of thread left after trimming
  3. The distance between the needle line and the cut fabric edge Correct answer.
  4. The gap between the needle plate and the feed dog

Explanation

Seam allowance is the margin of fabric between the stitching line and the raw edge, typically guided by a seam guide or the presser foot edge. It is a construction measurement, not a machine clearance. Thread tails, plate gaps and disc spacing are unrelated machine settings.

Question 37Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

A sewing operator wants a perfectly straight 10 mm seam allowance repeatedly on a lockstitch machine. Which attachment is most suitable?

  1. A ruffler attachment
  2. A seam guide (edge guide) set 10 mm from the needle Correct answer.
  3. A zipper foot
  4. A hemmer foot

Explanation

A seam guide or edge guide mounted on the machine bed or presser foot keeps the fabric edge at a fixed distance from the needle, giving a consistent seam allowance. Hemmer feet fold hems, zipper feet allow close stitching to zips, and rufflers make gathers. Only the edge guide directly controls the distance from the cut edge.

Question 38Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which attachment would be used to fold and stitch the bottom edge of a shirt neatly in one operation?

  1. Gathering foot
  2. Hemmer foot Correct answer.
  3. Piping foot
  4. Bias binder

Explanation

A hemmer foot has a scroll that turns the fabric edge under as it is fed, producing a neat folded hem in one pass. Bias binders apply binding tape, piping feet insert piping, and gathering feet create gathers. The scroll action of the hemmer is what makes it specific to hemming.

Question 39Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

What is the role of the bobbin case in a lockstitch machine?

  1. It cuts the thread after each seam
  2. It stores the needle thread
  3. It holds the bobbin and provides lower thread tension Correct answer.
  4. It drives the feed dog

Explanation

The bobbin case houses the bobbin and its tension spring controls the resistance on the bobbin thread as it unwinds. This lower tension must balance the upper tension to form a correct stitch. It does not store the needle thread, cut threads or drive the feed dog.

Question 40Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

An operator notices the stitch knot is pulled to the top surface of the fabric. Which adjustment should be made?

  1. Reduce the stitch length
  2. Increase the presser foot pressure
  3. Increase the bobbin case tension
  4. Loosen the needle thread tension or increase the bobbin tension as appropriate Correct answer.

Explanation

When the knot appears on the top, the bobbin thread is pulling the needle thread too strongly relative to the upper tension. The correction is to loosen the needle thread tension or increase bobbin tension so the knot sits inside the fabric. Presser foot pressure and stitch length affect feeding and density, not knot position.

Question 41Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which needle system is typically required for an industrial overlock machine?

  1. DPx5
  2. 135x5
  3. DBx1
  4. UY128GAS Correct answer.

Explanation

UY128GAS is the standard needle system for industrial overlock machines, with a shorter shank suited to the overlock needle bar. DBx1 is for domestic lockstitch, while DPx5 and 135x5 are industrial lockstitch needles. Using the wrong system affects needle height and loop formation on the looper.

Question 42Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

A lockstitch machine produces skipped stitches only when sewing thick denim over a thick seam. Which combination of causes is most likely?

  1. Bobbin wound too loosely
  2. Needle too fine or blunt, and hook timing slightly out Correct answer.
  3. Presser foot pressure too low
  4. Thread too fine for the needle eye

Explanation

Skipped stitches over thick seams usually indicate that the needle is too fine or has become blunt, or that the hook is not picking up the loop because timing is slightly off. A heavier needle and a timing check are the correct response. Bobbin winding, thread fineness and foot pressure affect other symptoms such as tension and feeding.

Question 43Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which statement correctly distinguishes a lockstitch from a chainstitch?

  1. A lockstitch interlocks a needle thread with a bobbin thread, while a chainstitch forms loops with one or more threads that unravel when the end is pulled Correct answer.
  2. A chainstitch cannot be used on knit fabrics
  3. A lockstitch is always stronger than a chainstitch
  4. A lockstitch uses one thread and a chainstitch uses two

Explanation

A lockstitch interlocks a needle thread with a separate bobbin thread, so it does not unravel easily from the end. A chainstitch forms interlocking loops from one or more threads and can unravel when the thread end is pulled. Strength depends on thread and seam type, and chainstitch is often used on knits.

Question 44Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

An operator wants to sew a curved neckline with a consistent 6 mm seam and no puckering on a lightweight knit. Which approach is most appropriate?

  1. Use a hemmer foot with coarse cotton thread
  2. Use a seam guide set at 6 mm, a ball point needle, fine polyester thread and balanced tension Correct answer.
  3. Use maximum presser foot pressure to prevent fabric movement
  4. Use a straight-stitch plate and heavy needle with tight upper tension

Explanation

A curved neckline on a lightweight knit needs a seam guide for consistent width, a ball point needle to avoid cutting yarns, fine thread and balanced tension to prevent puckering. Heavy needles, coarse thread or excessive foot pressure would distort the knit. The combination addresses width control, fabric protection and stitch balance together.

Question 45Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which statement about needle size selection for a given thread is correct?

  1. The needle eye should be just large enough for the thread, with the blade sized to the fabric Correct answer.
  2. The needle should always be the largest available to avoid breakage
  3. A finer needle is preferred for heavier fabric to reduce holes
  4. Needle size depends only on the machine model

Explanation

The needle eye must be large enough for the thread to pass without abrasion, while the blade must suit the fabric weight so it neither bends nor leaves holes. A needle that is too large for the thread causes poor loop formation, and one that is too fine for heavy fabric bends. Needle size is therefore matched to both thread and fabric.

Question 46Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

On an industrial overlock machine, which component carries the lower thread that interloops with the needle threads at the seam edge?

  1. The take-up lever
  2. The rotary hook
  3. The upper looper and lower looper Correct answer.
  4. The bobbin case

Explanation

Overlock machines form stitches by interlacing needle threads with two looper threads, so the loopers are the parts that carry the lower thread supply at the fabric edge. A rotary hook and bobbin case belong to lockstitch machines, which use a bobbin rather than loopers. The take-up lever controls thread feeding, not lower-thread interlacing.

Question 47Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which needle system designation is the standard one specified for most industrial single-needle lockstitch machines?

  1. DPx5
  2. DBx1 Correct answer.
  3. DCx1
  4. UY128GAS

Explanation

DBx1 is the common needle system for industrial lockstitch machines, with a flat shank and a standard length suited to these machines. DCx1 is used on some chainstitch and blindstitch machines, DPx5 is for heavy-duty and certain specialised machines, and UY128GAS is an overlock needle system. Using the wrong system changes needle length and scarf position, causing skipped stitches.

Question 48Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which thread numbering convention expresses thread size as the weight in grams of 1,000 metres of thread?

  1. Denier
  2. Tex Correct answer.
  3. Metric ticket number
  4. Cotton count

Explanation

Tex is defined as the weight in grams of 1,000 metres of thread, so a higher Tex value means a thicker thread. Cotton count and metric ticket number work in the opposite direction, where a higher number means a finer thread. Denier is based on the weight of 9,000 metres of filament yarn.

Question 49Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

An operator must sew a sharp curve on a medium-weight woven fabric and needs the seam to stay exactly parallel to the cut edge throughout. Which attachment is most suitable?

  1. A binder attachment
  2. A hemming folder
  3. A ruffler attachment
  4. A compensating presser foot with an edge guide Correct answer.

Explanation

A compensating or edge-guide foot has a guide that rides along the cut edge and keeps the seam distance constant while the operator steers the curve. Binders, hemming folders and rufflers perform folding or gathering tasks and do not maintain a fixed seam distance along a curved edge. The guide therefore addresses the parallel-seam requirement directly.

Question 50Industrial Sewing Machine Fundamentals: Types, Parts, Needles, Threads and Attachments

Which feed mechanism moves the fabric with a belt or roller running above and below the material, making it suitable for leather and other difficult-to-feed materials?

  1. Pull roller feed Correct answer.
  2. Drop feed
  3. Needle feed
  4. Walking foot (compound) feed

Explanation

A pull roller or roller feed uses powered rollers above and below the material to draw it forward, which suits leather and sticky or bulky materials. Drop feed uses only feed dogs below the fabric, needle feed moves the fabric with the needle bar, and walking foot feed uses a presser foot that moves with the feed dogs. Only the roller system grips the material from both surfaces continuously.