Threading and operating a sewing machine – Sewing Machine (Senior 3 Home Science) | Ganzaa

Sewing Machine

Lessons

Senior 3 · Home Science

Sewing Machine

4 lessons

Lesson 2 of 4

Threading and operating a sewing machine

25 min

Let's begin

Ishimwe sits at the school sewing machine for the first time. She threads it quickly, puts her fabric under the needle and presses the pedal. After ten centimetres the machine jams: underneath the fabric is a tangle of loose thread loops, the kind tailors call a "bird's nest". Nothing is broken. She threaded the top thread with the presser foot down, so the thread never sat between the tension discs. Almost every first-day problem with a sewing machine comes from threading or setting it up wrongly. This lesson takes you through the set-up step by step, then through sewing a straight seam, turning a corner and finishing off.

Definition

Threading: passing the top thread from the reel to the needle along the path set by the maker, and placing a wound bobbin in its case.

Stitch length: the distance between two needle holes, set in millimetres on the stitch length dial. Example: 2.5 mm for ordinary cotton.

Pivoting: turning the fabric round the needle while the needle is down in it, to sew a sharp corner.

Backstitching (reverse stitching): sewing back over the first and last few stitches of a seam with the reverse lever, so the seam does not unravel.

Setting up

Wind the bobbin. Put the reel on the spool pin, take the thread round the bobbin-winder guide, wind a few turns onto the empty bobbin by hand, put the bobbin on the winder spindle and push it across. On many machines, loosen the clutch knob in the centre of the hand wheel so the needle does not move. Run the machine until the bobbin is full, then return the winder and tighten the knob.
Insert the bobbin in its case, with the thread unwinding in the direction shown in the manual, and pull the thread through the slot and under the tension spring of the case.
Raise the presser foot (this opens the tension discs) and turn the hand wheel towards you until the needle and take-up lever are at their highest point.
Thread the top, following Figure 2.
Bring up the bobbin thread. Hold the end of the top thread, turn the hand wheel one full turn towards you, and pull the top thread: it brings up a loop of bobbin thread. Pull both ends about 10 cm to the back, under the presser foot.
Set the stitch length and test on a scrap of the same fabric, folded double.

Choosing needle, thread and stitch length

Fabric	Needle size (metric/US)	Stitch length	Example
Fine	7010 or 7511	about 2 mm	voile, chiffon, fine silk
Medium	8012 or 9014	2.5 mm	cotton, kitenge, polyester-cotton uniform fabric
Heavy	10016 or 11018	3 mm	denim, canvas, upholstery fabric
Knitted (stretch)	a ballpoint or stretch needle	a narrow zigzag	T-shirt jersey

A larger number means a thicker needle. Use general-purpose polyester or cotton thread of the same colour as the fabric, the same thread on top and in the bobbin.

Sewing a seam

Sit facing the needle, with good light, both feet ready on the pedal or treadle.
Pin the layers with the pins at right angles to the edge. Line up the raw edge with the guide line for the seam allowance (usually 1.5 cm).
Turn the hand wheel to put the needle into the fabric, then lower the presser foot.
Sew 3 or 4 stitches forward, hold the reverse lever for 3 or 4 stitches, then sew forward slowly. Guide the fabric lightly with both hands; do not pull or push it, because the feed dogs do the moving. Take out each pin before it reaches the foot.
At a corner: stop with the needle down in the fabric, raise the foot, turn the fabric, lower the foot and go on.
At the end: backstitch 3 or 4 stitches, turn the hand wheel until the needle is at its highest point, raise the foot, draw the fabric to the back and cut the threads, leaving 5 cm tails.

Luli Print: threading a sewing machine, winding a bobbin and fixing a bobbin mistake, step by step. Watch where the thread goes after the tension discs, and how the bobbin thread is brought up. The machine has an automatic needle threader; on a machine without one, thread the eye by hand.

Worked example

Worked example 1: counting stitches. A side seam is 60 cm long and the stitch length is set to 2.5 mm. About how many stitches does the machine make?

Change to the same unit: 60 cm = 600 mm.
$\text{number of stitches} = \frac{600\,\mathrm{mm}}{2.5\,\mathrm{mm}} = 240$
Answer: about 240 stitches. At 2 mm the same seam would need $\frac{600}{2} = 300$ stitches: shorter stitches are stronger but slower, and harder to unpick.

Worked example

Worked example 2: Ishimwe's bird's nest. Explain the tangle under her fabric and how to put it right.

The loops are underneath, which means the top thread was too loose: it was not held by the tension discs.
Cause: she threaded with the presser foot down, when the discs are closed, so the thread lay outside them.
Remedy: cut the tangle free, lift the presser foot, raise the needle to its highest point, and rethread the top thread completely from the spool pin.
Test on a scrap: both threads should lock in the middle of the fabric, with no loops on either side.

Warning

Safety at the machine. Keep fingers at least 2.5 cm from the needle and never put them under the presser foot while the machine can move. Unplug the machine, or take your feet off the treadle, before threading, changing the needle or the presser foot. Do not sew over pins: the needle can hit a pin and break, sending pieces of metal flying. Tie back long hair, and keep loose sleeves and jewellery away from the moving parts. Keep the cord off the floor where someone could trip over it.

Tip

Memory hook: "Foot up to thread, needle down to turn." Raise the presser foot before threading so the tension discs open; keep the needle down in the fabric whenever you stop to turn.

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Practice

Why must the presser foot be raised before threading the top thread?
List the order in which the top thread passes the parts of the machine.
How is the bobbin thread brought up through the needle plate?
Which needle size and stitch length would you choose for (a) denim and (b) cotton kitenge?
A hem is 1.2 m long and is sewn with 3 mm stitches. About how many stitches is that?
Describe how to sew a sharp, square corner on a cushion cover.
A student pushes the fabric through the machine with both hands to sew faster, and the needle keeps breaking. Explain why, and how the student should guide the fabric instead.

Show answersHide answers

Raising the foot opens the tension discs, so the thread can slip between them. Threaded with the foot down, the thread lies outside the discs, the top tension is lost and loops form underneath.
Spool pin → thread guide → between the tension discs → round the check spring → take-up lever → guides above the needle → needle eye.
Hold the end of the top thread, turn the hand wheel one full turn towards you, then pull the top thread to draw up a loop of bobbin thread.
(a) Denim: 10016 or 11018, about 3 mm. (b) Kitenge: 8012 or 9014, about 2.5 mm.
1.2 m = 1200 mm; $\frac{1200}{3} = 400$ stitches.
Sew to 1.5 cm from the edge, stop with the needle down in the fabric, raise the presser foot, turn the fabric through 90° round the needle, lower the foot and continue.
Pushing or pulling the fabric bends the needle while it is in the fabric, so it hits the needle plate and breaks. The feed dogs move the fabric: the sewer should only guide it lightly with both hands and control speed with the pedal.

Sources and credits

Lesson text, Figure 2, table, worked examples and practice: written by Ganzaa.
Photo: Needle plate, presser foot and needle with thread, Naberacka, Wikimedia Commons, public domain.
Video: How to thread a Sewing Machine, Wind a Bobbin, and Fix a Bobbin Mistake, Luli Print - Easy Sewing Tutorials, embedded from YouTube.

1Setting up

2Choosing needle, thread and stitch length

3Sewing a seam

Setting up

Choosing needle, thread and stitch length

Sewing a seam