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newSchoolWorks.com › VoTechWorks › Business & Cross-Cutting › Tailoring / Upholstery / Sewn Products › Industrial Sewing & Cutting Machines for Tailoring and Fabrication › Lesson 6
BUS-TAIL75-03 · Lesson 6 · 10 clock hours · lab

Cylinder-Arm Machine for Upholstery and Tailoring Details

Objective. Students maneuver a cylinder-arm machine to sew tubular and three-dimensional garment or upholstery components—cuffs, trouser legs, seat cushion sides—maintaining consistent seam allowance on curved work.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a credentialed professional in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

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What Is a Cylinder-Arm Machine?

A cylinder-arm industrial sewing machine has a narrow, horizontal tube—called the cylinder or cylinder arm—extending from the machine head in place of the flat bed found on standard flatbed machines. The cylinder arm is typically 4–6 inches in diameter and 8–12 inches long. Because fabric can slip around the arm in all directions, the machine excels at sewing closed, tubular, and three-dimensional workpieces that cannot lie flat. Common applications include trouser legs, cuffs, boot tops, gloves, seat-cushion boxing strips, and upholstery welting.

The Juki DU-1181N is a widely used walking-foot cylinder-arm machine. The walking foot (also called a compound feed or triple feed) moves the top and bottom fabric layers together, preventing slippage on thick, layered, or slippery upholstery materials. This is essential when sewing vinyl, leather, canvas, or multiple layers of foam-backed fabric.

Machine Setup

Needle selection. For upholstery and heavy tailoring work with bonded polyester thread (T-90 or T-135), use a size 18–21 needle (metric sizes 110–130). The needle must have a large enough eye to pass the thread without shredding it and a strong shank to resist deflection in dense materials. Size 19 (metric 120) is a practical starting point for T-90 bonded thread on medium-weight upholstery fabric or canvas.

Thread. Bonded polyester thread has a heat-set resin coating that keeps the plies together and reduces friction through the needle eye. T-90 is suited to lighter upholstery and marine canvas; T-135 is heavier and appropriate for thick vinyl or leather. Load the bobbin to manufacturer fill level—overfilling causes tension problems.

Foot. Install the walking presser foot appropriate to your material. Verify the foot clears the needle on both the left and right swing before sewing.

Seam-allowance guide. Attach the seam-allowance guide to the machine bed and set it to the target allowance—½ inch (12.7 mm) for this lesson. The guide rides against the fabric edge and keeps the stitch line parallel to it throughout the curve.

Tension and stitch length. For T-90 bonded thread on medium upholstery fabric, start with a stitch length of 8–10 stitches per inch (SPI) and balanced upper/lower tension. Test on a scrap of the same material and weight before moving to finished work.

Sewing Tubular and Three-Dimensional Work

Slide the workpiece over the cylinder arm with the open end toward you. Gravity pulls the free end down, keeping fabric away from the feed dogs and stitching area. Rotate the piece as you sew, keeping the seam-allowance guide in constant contact with the fabric edge. Do not stop mid-curve if you can avoid it; stopping and restarting often shifts the fabric and creates an offset in the seam. Practice smooth, controlled feeding—let the walking foot do the work rather than pulling the fabric.

For a fabric sleeve with a 6-inch diameter, one complete revolution of the tube equals roughly 18.8 inches of sewing (circumference = π × diameter). Maintain even speed—intermediate throttle rather than full speed—to keep control on tight curves.

Upholstery Welt Application

Welt cord (also called cording or piping cord) is a rope-like filler—usually twisted cotton or polyester—wrapped in a fabric cover strip. It is sewn into seams to create a raised, decorative, and protective edge on cushion boxing strips, furniture, and marine upholstery.

Procedure: Place the welt cord inside the fabric cover strip, fold the strip over it, and align the raw edges. Use a piping or zipper foot—or the walking foot with the needle positioned close to the cord—to stitch the cover tight against the cord. Then place this prepared welt between the boxing strip and the cushion panel, raw edges aligned, and stitch again on the cylinder arm, keeping the previous welt seam line just inside your current needle path to hide it in the finished piece.

Evaluate your finished welt against the quality standard card: the cord should be fully enclosed, the cover fabric should not pucker, the seam allowance should be within ±2 mm of the ½-inch target along the full 24-inch length, and there should be no broken stitches or skipped stitches.

Safety

Machine guarding. Keep the needle guard and hand wheel cover in place. Never reach under the presser foot while the machine is energized.

Lockout/tagout (LOTO). When changing the needle, presser foot, or bobbin, turn the machine off and—in a shop with multiple machines on shared power—follow your facility's LOTO procedure before opening any access panel.

PPE. Wear ANSI-compliant safety glasses when sewing at industrial speeds; broken needles can eject fragments. Keep loose sleeves and hair secured away from the moving parts.

Needle disposal. Discard broken or bent needles in a designated sharps container, never in an open trash bin.

Posture and ergonomics. Position the chair so forearms are roughly parallel to the floor. Take short breaks to prevent repetitive-strain fatigue when sewing continuous curved seams.

Quality Check

Use a seam gauge or ruler to measure the actual seam allowance at five points along the finished boxing strip. Calculate the deviation from the ½-inch (12.7 mm) target at each point. A score of 80% or higher on the instructor quality card—covering allowance accuracy, stitch integrity, and welt appearance—constitutes a passing result for this lab.

Key terms9

Cylinder armThe narrow horizontal tube projecting from a cylinder-arm machine that allows tubular or three-dimensional workpieces to be slipped over it and sewn on all sides.
Walking foot (compound feed)A presser foot mechanism that feeds the top layer of fabric in sync with the bottom feed dogs, preventing slippage on thick or layered materials.
Bonded polyester threadA multi-ply polyester thread coated with a heat-set resin that bonds the plies together, reducing fraying and friction through the needle eye; rated by ticket size (e.g., T-90, T-135).
Seam-allowance guideAn adjustable attachment fixed to the machine bed that rides against the fabric edge to maintain a consistent, measured distance between the edge and the stitch line.
Welt cord (piping cord)A rope-like filler material enclosed in a fabric cover strip, then sewn into a seam to create a raised decorative and protective edge on upholstered or fabricated products.
Boxing stripThe band of fabric that forms the side wall of a cushion, connecting the top and bottom panels and giving the cushion its three-dimensional shape.
Stitch length (SPI)The number of stitches per inch; a common upholstery range is 8–10 SPI, balancing seam strength with fabric integrity.
Lockout/tagout (LOTO)An OSHA-based safety procedure requiring that machinery be de-energized and physically locked before maintenance or adjustment tasks—such as needle changes—are performed.
T-90 / T-135 threadIndustry ticket-size designations for bonded polyester thread; T-90 is lighter and used for canvas and medium upholstery, while T-135 is heavier and suited to thick vinyl or leather.

Worked examples4

1. You need to verify your seam allowance is within ±2 mm of the ½-inch target. After sewing a 24-inch boxing strip, you measure the allowance at five points and get these values (in mm): 14, 13, 12, 11, 15. Is the seam within tolerance? Which points fail?
  1. Convert the target: ½ inch = 12.7 mm. Round the tolerance band: acceptable range = 12.7 − 2 = 10.7 mm to 12.7 + 2 = 14.7 mm.
  2. Check each measurement against the range 10.7–14.7 mm: 14 mm — within range (pass); 13 mm — within range (pass); 12 mm — within range (pass); 11 mm — within range (pass); 15 mm — 15 > 14.7, outside range (fail).
  3. Count passing points: 4 out of 5.
Answer: Four of the five measurement points are within the ±2 mm tolerance. The fifth point at 15 mm exceeds the upper limit of 14.7 mm and fails. The seam needs correction at that location before submission.
2. A fabric sleeve has a diameter of 6 inches. Approximately how many inches of seam will you sew to complete one revolution around the cylinder arm?
  1. Recall the circumference formula: C = π × d, where d = diameter.
  2. Substitute: C = 3.1416 × 6 inches.
  3. Calculate: C = 18.85 inches, rounded to 18.9 inches.
Answer: One complete revolution around the 6-inch-diameter sleeve requires approximately 18.9 inches of sewing.
3. You are sewing at 8 SPI and your boxing strip seam is 24 inches long. How many stitches will the finished seam contain?
  1. Identify the variables: stitch length = 8 stitches per inch; seam length = 24 inches.
  2. Multiply: total stitches = 8 SPI × 24 inches = 192 stitches.
  3. Add backstitches: if you backstitch 4 stitches at each end, total = 192 + 4 + 4 = 200 stitches.
Answer: The seam contains 192 forward stitches. Including a 4-stitch backtack at each end, the total stitch count is 200.
4. Your seam-allowance guide is set to ½ inch. You realize the finished product requires a ⅜-inch seam allowance. How many millimeters do you need to move the guide, and in which direction?
  1. Convert both measurements to millimeters: ½ inch = 12.7 mm; ⅜ inch = 9.525 mm.
  2. Calculate the difference: 12.7 − 9.525 = 3.175 mm.
  3. Determine direction: the target allowance is smaller, so the guide must move closer to the needle by approximately 3.2 mm.
Answer: Move the seam-allowance guide approximately 3.2 mm (about ⅛ inch) closer to the needle to achieve the narrower ⅜-inch seam allowance.

The math in this lesson1

Learners convert ½ in to 12.7 mm and check seam measurements against a ±2 mm band.
N-Q.1
Brush up in the math halls at newSchoolWorks.com:
In class: Setup practice: students install the correct needle (size 19 bonded-thread needle) and foot for upholstery thread, thread the machine, and produce a sample seam on flat fabric before moving to 3-D work. · Cylinder work drill: students sew a finished seam around a sewn tube (fabric sleeve, 6-inch diameter) without stopping the machine mid-curve, guided by a seam-allowance guide set to 1/2 inch. · Upholstery welt application: students sew a 24-inch length of welt cord into a cushion boxing strip using the cylinder arm, then evaluate the finished piece against an instructor-produced quality standard card.
Materials: Cylinder-arm industrial machine (Juki DU-1181N or equivalent), bonded polyester thread (T-90 or T-135), size 18–21 needles, fabric tube samples, upholstery welt cord, seam-allowance guide, quality standard card
Check: Student sews a complete welt-cord boxing strip with seam allowance within ±2 mm of target and no broken stitches; pass = instructor quality-card evaluation score of ≥80%.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Equipment Operation and Maintenance
1. What is the primary advantage of a cylinder-arm machine over a standard flatbed machine for sewing trouser legs or cushion boxing strips?
Materials and Thread Selection
2. When threading a cylinder-arm machine for upholstery work with T-90 bonded polyester thread, which needle size range is appropriate?
Workplace Safety and Regulatory Compliance
3. Before changing the needle on a cylinder-arm machine in a multi-machine shop, what safety procedure must be followed?
Quality Control and Inspection
4. A student measures the seam allowance on a finished boxing strip at five points: 11 mm, 13 mm, 16 mm, 12 mm, and 14 mm. The target is 12.7 mm ± 2 mm. How many points fall outside the acceptable range?
Equipment Operation and Maintenance
5. What function does a walking foot (compound feed) serve when sewing thick upholstery materials on a cylinder-arm machine?
Upholstery Construction Techniques
6. When applying welt cord to a boxing strip, why is the first stitching line (enclosing the cord in its cover strip) placed just inside the second stitching line in the finished seam?
Measurement and Calculation
7. A cylinder arm has a diameter of 5 inches. Approximately how far will the operator sew to complete one full revolution of a fabric tube fitted snugly over it?
Workplace Safety and Regulatory Compliance
8. Which personal protective equipment (PPE) is specifically recommended when operating a cylinder-arm industrial sewing machine at production speeds?
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