Machine troubleshooting: most everyday sewing machine problems are minor and easily repaired. Learn to diagnose and fix the 10 most common problems to keep your machine in excellent condition.
Uneven or inconsistent stitches are usually caused by the needle. Dull or bent needles cause skipped stitches by not consistently connecting the upper thread with the bobbin thread. Replace the needle with a new one to correct the problem. Should the skipped stitches persist, check that the thread and the needle are compatible. Finer-point needles have smaller numbers and work best with fine, lightweight thread designated by a higher number; the opposite is true with heavier, thicker-point needles. The thread should fit in the groove that runs down the needle front where it's cradled. This groove protects the thread during stitching. If the thread is too large or too small for the groove, change either the needle or the thread to eliminate skipped stitches.
Skipped stitches, gathered or puckered fabric, thread loops or other malformed stitches are all indications of tension problems. The tension settings on modern sewing machines work far better than previous models, making it easier to correct any problems that arise. Understanding the relationship between the needle thread and the bobbin thread is essential to understanding tension. Proper stitches form when the needle thread and bobbin thread lock together in the fabric and each thread lies on the fabric surface without pulling or puckering it (1).
A tight upper thread will pull the bobbin thread up to the fabric right side (2). Reduce the needle tension to relax the upper thread and keep it from pulling the bobbin thread to the fabric right side.
A loose upper thread will be pulled to the fabric wrong side by the bobbin thread, causing loops on the fabric wrong side (3). Increase the needle tension to a higher number to keep the upper and lower thread balanced.
Test your machine's tension by threading the machine with two different colors of the same thread type and weight in the needle and bobbin. Stitch a line and examine the fabric right and wrong side (4). Each side should show only one thread color; if two colors show on either side, a tension adjustment is needed. Upper thread tension adjustments are required frequently as fabrics and thread weights change. Changing the bobbin tension isn't difficult, but is best adjusted using specialized tools. Ask a trained technician to adjust the bobbin tension using the appropriate gauges and weights when necessary.
Listen to your sewing machine when it's functioning properly and learn its normal sounds. When those sounds change, it's an early indication there's a problem.
If there's a popping sound while the needle pierces the fabric, the point is dull. Replace the needle to correct the problem.
If there's a rattling sound or if the machine seems noisier when stitching, the machine needs oil. Consult the owner's manual for oiling instructions, including where to oil, how frequently, how much oil is needed and what type of oil to use.
Repeat thread breakage is caused by many factors. Check the thread on the spool. Old thread grows dry and brittle, weakening it and causing it to snap when in use. Bargain thread is made of short pieces, called staples, twisted together. This short-staple thread is weak and breaks easily in comparison to quality long-staple thread. Short-staple thread sheds more lint and fuzz into the machine, potentially causing damage. If the thread is old or inferior, replace it with quality, long-staple thread to correct the problem.
An incorrect tension setting also causes thread breakage. When too much tension is placed on thread, it's pulled tight, often to the point of breaking. Re-adjust the tension settings to correct the problem.
Improper threading causes a bird's nest to form on the fabric wrong side. If this occurs from the beginning of sewing, the presser foot was lowered during threading. When the presser foot is down the needle tension is engaged, causing the two tension discs to close and not allow the thread to pass through. Raise the presser foot and rethread the machine to correct the problem.
Should a bird's nest form during sewing, the thread has slipped out of one or more thread guides. Raise the presser foot and rethread the machine to correct the problem.
Needles break when they strike the stitch plate or the presser foot. If the needle is bent, it will hit the throat plate or presser foot as it stitches. Replace the bent needle to solve the problem.
Needle breakage also occurs when the machine operator moves the fabric, pulling it when the needle is down and piercing the fabric. This distorts the needle, causing it to hit the throat plate or the foot. To move the fabric while sewing, learn the rhythm of the machine first, practicing only moving the fabric when the needle is raised. Otherwise, avoid moving the fabric and let the feed dogs do the work.
Using the needle in the wrong position also causes the needle to break. Some presser feet, such as zipper or piecing feet, may require a specific needle position to function properly. Learn the necessary needle position required before using a new foot.
Puckering occurs most frequently when sewing woven fabrics and has many causes. If the stitch length isn't long enough for the thread to lie flat, the thread gathers the fabric, causing it to pucker. Lengthen the stitch to correct the problem.
Using incompatible fabric and thread also causes puckering. A heavyweight thread on a lightweight fabric also causes the fabric to gather and pucker. Use a compatible thread weight and an appropriate needle for every fabric.
Uneven feeding also causes puckering as the lower fabric layer is fed through the machine faster than the upper layer. Hold the fabric taut in front and behind the needle but don't stretch it. When the fabric is released, it will relax and the seam will be flat and pucker free.
Improper Stitch Formation
If a decorative stitch pattern doesn't form properly, check the presser foot underside. Small differences in presser feet make a big difference in stitch results. A slight indentation in front and behind the needle opening allows a stitch pattern with forward and backward movement to form properly (5). Select and attach the appropriate presser foot for the stitch to eliminate this problem. An open-toe foot often works well when using many decorative stitches, but always reference the machine manual to determine the ideal foot.
No Stitch Forming
If the machine doesn't form a stitch, it's likely a problem with the timing. Timing refers to how the needle and bobbin work together to lock the threads into a stitch. Contact a factory-trained technician to make the required adjustments to correct the problem.
TIP: Replace broken needles immediately but make sure to find all the needle parts before continuing to sew. If the needle tip falls under the throat plate, the machine could be severely damaged.
Check out the Schmetz needle app featured in "Cool Tools" on page 15 to find the perfect needle for every project.
RELATED ARTICLE: TNT: THREAD, NEEDLE, TENSION
Refer to this quick checklist the next time your sewing machine encounters a problem.
* Is the thread dry, brittle, or faded? Yes--replace with new thread.
* Are the thread and fabric compatible? No--use lightweight thread for fine fabric, heavyweight thread for thick fabric.
* Is the needle the correct size for the thread? No--replace either the thread or needle.
* Is the needle bent or burred? Yes--replace with a new needle.
* Is the needle sharp? No--replace with a new needle.
* Is the needle compatible with the fabric and thread? No--replace with the appropriate sized needle.
* Was the machine properly threaded? No--raise the presser foot and rethread the machine.
* Is the presser foot lowered during sewing? No--lower the presser foot.
* Are the needle and bobbin tension balanced? No--adjust the upper thread tension as needed.
Still not functioning?
Take the machine to a trained technician for maintenance.
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|Title Annotation:||Basic Skills|
|Date:||Dec 1, 2013|
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