How To Fix Tension Sewing Machine & Get Perfect Stitches

by

Bad stitches on your sewing machine often come from tension problems. You can fix sewing machine tension yourself and get perfect stitches by checking and adjusting the thread tightness on both the top and bottom of your machine. This guide shows you how.

How To Fix Tension Sewing Machine
Image Source: blogger.googleusercontent.com

Grasping Sewing Machine Tension

Sewing machine tension is about how tight the thread is. Think of it like a little tug-of-war. The top thread and the bobbin thread pull against each other to form a stitch. For a good stitch, the pull from both sides must be just right, and balanced.

The machine has parts that control this pull.
* The upper thread tension is usually controlled by a dial or discs on the front or side of the machine. The thread passes through these discs.
* The bobbin tension is controlled by a small spring and screw on the bobbin case (for machines with removable cases) or a built-in system (for drop-in bobbins).

When the pull is balanced, the two threads meet right in the middle of the fabric layers you are sewing. This makes a neat, strong stitch that looks the same on the top and the bottom of the fabric.

Why Tension Gets Out of Whack

Many things can cause sewing machine tension problems. It’s not always the tension dial itself being set wrong. Often, something simple throws off the balance. Think of these like small bumps in the road for your thread.

Here are common reasons tension goes bad:

  • Lint and Dust: Small bits of thread and fabric dust build up in the tension discs or in the bobbin area. This stops the thread from moving smoothly.
  • Thread Not Put In Right: If the upper thread skips a guide or isn’t seated fully in the tension discs, the tension won’t work right.
  • Bobbin Problems: The bobbin might be wound unevenly. Or it might be put into its case or holder the wrong way. Lint in the bobbin case is also a big problem.
  • Wrong Needle: Using the wrong needle for the fabric, or a bent or dull needle, can mess up how the thread passes through the fabric, affecting how stitches form.
  • Bad Thread: Old thread can lose its strength. Poor quality thread might have thick or thin spots. Both make tension uneven.
  • Fabric Trouble: Very thick or very thin fabrics need careful handling. The standard tension setting might not work well.
  • Machine Needs Cleaning or Oil: A dry or dirty machine doesn’t run smoothly. This can make thread feed unevenly.
  • Presser Foot Issues: If the presser foot pressure is wrong, it can change how the fabric moves, impacting tension.

These are all part of general sewing machine troubleshooting. Before you even touch the tension dials, it’s good to check these basic things.

Seeing Bad Stitches

Your stitches tell you if the tension is off. Look closely at your sewing line. Uneven stitches sewing machine problems show up in specific ways. Here’s what to look for:

  • Loops on Top of the Fabric: This usually means the upper thread tension is too loose, or the bobbin tension is too tight. The loose top thread is being pulled down to the bottom.
    • How it looks: The top thread lies in loose loops on the surface.
  • Loops on the Bottom of the Fabric: This usually means the bobbin tension is too loose, or the upper thread tension is too tight. The loose bobbin thread is being pulled up to the top. This is the most common problem people see.
    • How it looks: The bobbin thread lies in loose loops on the bottom surface.
  • Stitches Look Too Tight: The fabric might pucker or gather along the seam line. The thread looks like it’s pulling too hard on the fabric.
    • How it looks: The seam line looks wavy or bumpy.
  • Stitches Look Too Loose: The seam might pull apart easily. The stitches look flat and don’t sink into the fabric much.
    • How it looks: The thread lies flat on the surface; pulling the seam might show gaps.
  • Skipping Stitches: The machine misses making a stitch every now and then. This can be a tension problem (thread isn’t feeding right) but is often a needle or timing issue.
    • How it looks: There are gaps in your stitching line.
  • Thread Breaks: The top or bottom thread snaps while you are sewing. This can happen if tension is much too tight, but also from a bad needle, wrong thread, or dirt.
    • How it looks: Sewing stops, and you find a broken thread end.

Looking at these signs helps you figure out which tension (top or bottom) might be the main problem.

The Right Way to Check Tension: The Test Sample

You can’t guess tension settings. You must test them on fabric. This is your sewing tension guide.

Here is the best way to do it:

h4. Preparing Your Test Fabric

  1. Get Fabric: Use a scrap of the exact fabric you plan to sew your project with. Double it over so you are sewing through two layers.
  2. Choose Thread: Use two different colors of thread. Put one color in the needle (top thread) and a clearly different color in the bobbin (bottom thread). This makes it easy to see which thread is which in the stitch.
  3. Set Machine: Set your machine to a straight stitch. A medium stitch length is good, like 2.5 mm.

h4. Sewing Your Test Lines

  1. Sew several lines of straight stitches on your test fabric. Sew for at least 3-4 inches for each line.
  2. Try sewing some lines on the straight grain and maybe one on the bias (diagonal) if your fabric allows.
  3. Do not backstitch at the start or end. Just sew off the edge.

h4. Looking at Your Test Stitches

  1. Take the fabric out.
  2. Look closely at the stitches on the top side. You should see lines of your top thread color.
  3. Look closely at the stitches on the bottom side. You should see lines of your bobbin thread color.
  4. Now, look at the side of the fabric layers, right in the middle. This is where the top and bottom threads should meet and lock together.

h4. Interpreting the Stitch Sample

  • Perfect Tension: The stitches look the same on the top and the bottom. When you look at the side (between the two fabric layers), you should see the two threads twisted together neatly, right in the middle of the fabric layers. It looks like a small, balanced knot inside the fabric.
  • Top Thread Too Loose (or Bobbin Too Tight): The top thread makes loops on the top surface. On the bottom, the stitches might look very straight with no sign of the top thread pulling through.
  • Bottom Thread Too Loose (or Top Too Tight): The bobbin thread makes loops on the bottom surface. On the top, the stitches might look very straight with no sign of the bobbin thread pulling through.

This test sample is your map to fixing tension.

Working on Upper Thread Tension

Most of the time, when tension is bad, you start by fixing the upper thread tension. This is the easiest to adjust.

h4. Finding the Upper Tension Control

  • Look on the front or side of your machine. You will see a dial, knob, or buttons with numbers. This is your upper tension control.
  • Higher numbers usually mean tighter tension. Lower numbers mean looser tension.

h4. Steps to Adjust Upper Tension

  1. Lift Presser Foot: Always lift the presser foot before threading the top thread or adjusting tension. This opens the tension discs, letting the thread sit in properly. If the foot is down, the discs are closed, and the thread won’t go in correctly.
  2. Re-thread the Top: Take the top thread out completely. Thread the machine again carefully, making sure the thread goes through every guide and snaps firmly into the tension discs (with the presser foot UP). This fixes many simple problems like skipped guides or trapped lint.
  3. Check Your Test Sample Again: After re-threading, sew another test line. Sometimes, just re-threading fixes the issue.
  4. Make Small Adjustments: If the tension is still off based on your test sample:
    • If you have loops on top, the top thread is too loose. Turn the upper tension dial to a slightly higher number. Maybe go from 4 to 5, or 3 to 3.5.
    • If you have loops on bottom, the top thread is too tight. Turn the upper tension dial to a slightly lower number. Maybe go from 4 to 3, or 5 to 4.5.
  5. Sew Another Test Sample: After changing the dial, sew another test line on your fabric scrap.
  6. Check Stitches: Look at the new stitches. Are they better? Worse?
  7. Repeat: Keep making small changes to the upper tension dial (one number or half a number at a time) and sewing new test lines until the stitches look balanced on your fabric.

Most tension problems can be fixed just by adjusting sewing tension on the upper thread dial. Only move to the bobbin tension if adjusting the upper thread doesn’t fix loops on the bottom.

Working on Bobbin Tension

Adjusting bobbin tension is often needed less often than upper tension. But if you have done everything with the upper thread and still have loops on the bottom of your fabric, the bobbin tension might be the problem.

Important Warning: Be very careful when adjusting bobbin tension. The screw is tiny, and turning it too much or losing it is easy. Only adjust bobbin tension if you are comfortable doing so and have a good reason (like consistent bottom loops that upper tension adjustments can’t fix).

h4. Different Bobbin Types

  • Removable Bobbin Case: Most older machines and some newer ones have a metal bobbin case that you take out. This case has a small screw on the side.
  • Drop-in Bobbin: Many newer machines have a bobbin that drops directly into the machine from the top. These often have a less adjustable bobbin tension, or it’s harder to get to. Check your machine’s manual. For many drop-in systems, you fix bottom loops by tightening the upper tension, not adjusting the bobbin itself.

We will focus on adjusting the removable bobbin case here, as it is the main type with an easy-to-access adjustment screw.

h4. Adjusting a Removable Bobbin Case

  1. Take Out the Case: Remove the bobbin case from your machine.
  2. Look at the Screw: Find the tiny screw on the side of the bobbin case, near where the thread comes out under a small metal spring.
  3. Get a Small Screwdriver: You need a tiny screwdriver that fits the slot on the screw head perfectly. A jeweller’s screwdriver set is useful.
  4. Make Tiny Turns:
    • If you have loops on the bottom (meaning bobbin tension is too loose), you need to make the bobbin tension tighter. Turn the screw a tiny amount clockwise (to the right). Think of turning it like the hands on a clock moving one or two “minutes.”
    • If you are getting loops on the top even with upper tension very loose (meaning bobbin tension is too tight – less common), you need to make the bobbin tension looser. Turn the screw a tiny amount counter-clockwise (to the left).
  5. The “Drop Test” (for metal bobbin cases): This is a common way to check metal bobbin case tension.
    • Put the bobbin in the case.
    • Pull the thread tail out, holding the end. The thread should come from under the tension spring on the case.
    • Hold the thread tail so the bobbin case hangs down freely.
    • Give the thread a gentle tug upwards.
    • Good tension: The bobbin case should slowly drop down about 1-2 inches with the tug. It shouldn’t drop freely without a tug, and it shouldn’t stay stuck no matter how much you tug.
    • Too loose: The case drops freely without a tug. Tighten the screw tiny bit clockwise.
    • Too tight: The case doesn’t drop much or at all even with a firm tug. Loosen the screw tiny bit counter-clockwise.
    • Repeat adjusting and testing until the drop is right.
  6. Put Case Back: Place the adjusted bobbin case back in the machine.
  7. Sew Another Test Sample: Crucially, sew a new test line on your fabric scrap.
  8. Check Stitches: How do they look?
  9. Repeat if Needed: If still not right, take the case out and adjust the screw another tiny bit. Test again.

This process of bobbin case adjustment is delicate. Go slow. Small turns make a difference. Always test after each adjustment.

Fixing Specific Stitch Problems

Let’s combine what we know and look at specific issues you might see and how to use adjusting sewing tension and other checks to fix them.

h4. Loops on Top of Fabric

  • Look like: Loose loops of the top thread visible on the top side of your fabric.
  • Main Cause: Upper thread tension is too loose, OR bobbin tension is too tight.
  • Fix Steps:
    1. Lift presser foot. Re-thread the top thread carefully.
    2. Sew test sample. Check again.
    3. If still looping, increase (tighten) the upper tension dial setting slightly.
    4. Sew test sample. Check.
    5. Repeat step 3 and 4 until loops disappear.
    6. Rarely, if upper tension is very high and you still have top loops, the bobbin tension might be way too tight. If you have a removable case, check its tension (drop test) and loosen the screw a tiny bit if needed (remember the caution!). For drop-in bobbins, this is very unlikely to be the bobbin itself; re-threading top and checking the thread path is key.

h4. Loops on Bottom of Fabric

  • Look like: Loose loops of the bobbin thread visible on the bottom side of your fabric.
  • Main Cause: Upper thread tension is too tight, OR bobbin tension is too loose. (Most often, it’s the upper tension being too tight relative to the bobbin).
  • Fix Steps:
    1. Lift presser foot. Re-thread the top thread carefully. Ensure it’s seated in the tension discs.
    2. Check the bobbin: Is it wound evenly? Is it inserted correctly in the case or machine? Is there lint in the bobbin area or case? Clean it out.
    3. Sew test sample. Check again.
    4. If still looping, decrease (loosen) the upper tension dial setting slightly.
    5. Sew test sample. Check.
    6. Repeat step 4 and 5 until loops disappear.
    7. If you have turned the upper tension very low (like 1 or 0) and still have bottom loops, the bobbin tension is likely too loose (if you have a removable case). If you have a removable case, take it out, check its tension (drop test) and tighten the screw a tiny bit clockwise if needed. For drop-in bobbins, first try a new bobbin, make sure it’s inserted correctly, and ensure the area is clean. If the problem persists, it might need a service call for internal bobbin tension adjustment.

h4. Stitches Too Tight (Fabric Puckering)

  • Look like: The fabric gathers along the seam line. Stitches are very flat and hard to see.
  • Main Cause: Both upper and bobbin tension are probably too tight for the fabric. Or presser foot pressure is too high.
  • Fix Steps:
    1. Decrease (loosen) the upper tension dial setting.
    2. Sew test sample. Check.
    3. Repeat step 1 and 2 until puckering stops.
    4. If upper tension is very low and it still puckers, bobbin tension might be too tight. If you have a removable case, check its tension (drop test) and loosen the screw tiny bit if needed.
    5. Check your presser foot pressure (if adjustable on your machine). Reduce the pressure slightly.
    6. Consider using a lighter thread or needle, or a stabilizer under the fabric.

h4. Stitches Too Loose (Seam Weak)

  • Look like: Stitches lie flat on the fabric, easy to pull apart. No slight sinking into the fabric.
  • Main Cause: Both upper and bobbin tension are likely too loose for the fabric.
  • Fix Steps:
    1. Increase (tighten) the upper tension dial setting.
    2. Sew test sample. Check.
    3. Repeat step 1 and 2 until stitches look balanced and firm.
    4. If upper tension is very high and stitches are still loose, bobbin tension might be too loose. If you have a removable case, check its tension (drop test) and tighten the screw tiny bit if needed.

h4. Skipping Stitches Sewing

  • Look like: Gaps in your stitch line where no stitch formed.
  • Causes: Often not just tension, but can be related. Most common causes are:
    • Bent or Dull Needle: The most frequent reason.
    • Wrong Needle: Using a universal needle on knit fabric, or a needle too large/small.
    • Threading Issues: Upper thread not seated correctly in tension discs or guides.
    • Bobbin Issues: Bobbin thread not feeding smoothly (lint, wound badly, bobbin in backwards).
    • Timing is Off: The machine’s hook isn’t meeting the needle at the right moment (needs repair).
  • Fix Steps:
    1. Change the Needle: Always do this first for skipping stitches. Use a brand new, correct type/size needle for your fabric.
    2. Re-thread the machine completely, top and bottom. Make sure the presser foot is UP when threading the top.
    3. Clean out the bobbin area very well.
    4. Check your upper and bobbin tension using a test sample. Ensure they are balanced. Sometimes extreme looseness can contribute.
    5. If none of the above works, the machine might need service for timing issues.

h4. Thread Breakage Sewing

  • Look like: The thread snaps while you are sewing.
  • Causes: Can be tension, but also many other things:
    • Tension Too Tight: Especially upper tension.
    • Bad Thread: Old, weak, knotty, or cheap thread.
    • Bad Needle: Bent, dull, or burred needle can fray and snap thread. Wrong size/type.
    • Incorrect Threading: Thread catching on a guide, not through a take-up lever hook, etc.
    • Lint or Obstructions: Dirt in the thread path, tension discs, or bobbin area.
    • Bobbin Issues: Bobbin wound too full or unevenly, catching in the case.
    • Machine Needs Oil: Friction causes heat and breaks thread.
  • Fix Steps:
    1. Check your tension settings. If they are very high, loosen the upper tension.
    2. Change the needle.
    3. Re-thread the machine completely.
    4. Check your thread – try a new spool of good quality thread.
    5. Clean the machine thoroughly, especially the thread path and bobbin area.
    6. Check your bobbin winding. Re-wind it if needed, making sure it’s smooth.
    7. Check for rough spots anywhere the thread touches (on the machine itself, guides, etc.).
    8. Oil your machine if it needs it (check your manual).

Checking More Than Just Tension

As you can see from skipping stitches and thread breaking, other things hugely impact stitch quality and can be mistaken for sewing machine tension problems. Always check these basics first or along with your tension adjustments. This is key to sewing machine troubleshooting.

h4. Your Needle Matters

  • Is it the right type for your fabric (universal, ballpoint, denim, etc.)?
  • Is it the right size? Too big leaves big holes, too small can break or skip.
  • Is it bent or dull? Run your finger gently down the point (away from you!). If it feels rough or looks even slightly bent, change it.
  • Is it inserted correctly? Pushed all the way up and facing the right way?

h4. Your Thread Matters

  • Are you using good quality thread? Cheap thread often has slubs or unevenness.
  • Is the thread old? It can become weak and break easily.
  • Is the thread type right for your fabric and needle? (e.g., thick thread needs a larger needle).

h4. Clean Your Machine

  • Lint builds up everywhere: in tension discs, under the needle plate (around feed dogs), in the bobbin case area.
  • Lint stops thread from moving freely and evenly.
  • Use a small brush to clean these areas often. Don’t use canned air in some areas, as it can blow lint further inside. Check your manual.

h4. Oil Your Machine

  • Moving metal parts need oil to run smoothly. Friction makes things heat up and work unevenly.
  • Check your manual for where and how often to oil.

h4. Check Presser Foot Pressure

  • Some machines let you adjust how hard the presser foot pushes on the fabric.
  • Too much pressure can stretch or pucker thin fabrics, making tension look bad.
  • Too little pressure means the feed dogs don’t move the fabric evenly, leading to uneven stitches.
  • Check your manual for how to adjust this if your machine has the feature.

Your Steps to Great Tension

Here is a summary of the best way to fix tension problems and get back to perfect stitches. Think of this as your step-by-step sewing tension guide.

  1. Basic Checks First:
    • Is the machine threaded correctly, top and bobbin? (Presser foot UP when threading top!).
    • Is the bobbin wound evenly and put in right?
    • Is the needle new, straight, correct type/size, and inserted right?
    • Are you using good quality thread suited to the fabric?
    • Is the machine clean, especially the thread path and bobbin area?
  2. Prepare a Test Sample: Get two layers of your project fabric. Use two different thread colors (top and bottom).
  3. Sew Test Lines: Stitch several straight lines on the test fabric scrap.
  4. Look at Your Stitches: Check both the top and bottom sides. See if there are loops or if stitches are too tight/loose. Look at the side to see where the threads meet.
  5. Adjust Upper Tension First:
    • If you have loops on top, turn the upper tension dial up a tiny bit (tighten).
    • If you have loops on bottom, turn the upper tension dial down a tiny bit (loosen).
  6. Sew ANOTHER Test Sample: After each tension change, sew a new line of stitches.
  7. Check Stitches Again: See if the change made things better.
  8. Repeat Upper Tension Adjustment: Keep making small changes to the upper tension dial and sewing test lines until the stitches look balanced.
  9. Consider Bobbin Tension (If Necessary): Only if you have tried adjusting the upper tension fully and still have bad loops on the bottom (and you have a removable metal bobbin case), consider adjusting the bobbin case screw.
    • Take out the bobbin case.
    • Turn the tiny screw clockwise a very tiny amount to tighten (for bottom loops).
    • Use the drop test if helpful.
    • Put the case back and sew a new test sample.
    • Adjust the bobbin screw in tiny steps and test again until stitches are good.
  10. If Still Stuck: Go back and check the “More Than Just Tension” items again very carefully. If problems continue, the machine may need professional service.

Getting tension right is about making small changes and testing. Don’t turn the dials or screws a lot at once. A little change goes a long way.

More Ideas for Perfect Stitches

  • Different Fabrics: Thicker fabrics often need slightly higher tension than very thin ones. Stretchy fabrics can be tricky and sometimes need lower tension or special needles/techniques. Always test on your specific fabric!
  • Specialty Threads: Using thicker decorative threads (like topstitching thread) usually means you need to loosen your upper tension a lot. You might also need a larger needle and potentially special settings for the bobbin thread too (sometimes using regular thread in the bobbin).
  • Machine Manual: Your machine’s manual is your best friend! It will show you where all the parts are and might have specific tension tips for your model. It might also suggest a starting tension number for normal sewing. This is a great sewing tension guide specific to your machine.

Keeping Your Machine Happy

Regular cleaning and oiling prevent many sewing machine tension problems and other issues.

h4. Cleaning Routine

  • After Each Project (or every 8-10 hours of sewing):
    • Remove the needle.
    • Remove the presser foot.
    • Remove the bobbin and bobbin case/cover.
    • Remove the needle plate (usually needs a screwdriver).
    • Use a small brush to gently sweep out all the lint from the bobbin area, feed dogs (the little teeth that move the fabric), and under the needle plate.
    • Brush around the upper tension discs as much as you can reach.
    • Put everything back together.
  • Deeper Clean (less often): Sometimes you need to get into the machine more. If you feel comfortable, follow your manual’s directions for cleaning other areas. Never force anything open.

h4. Oiling Routine

  • Check your manual for where and how often to oil. Different machines need oil in different spots.
  • Typically, a drop of sewing machine oil is needed on moving metal parts, especially in the bobbin area and possibly other points.
  • Only use proper sewing machine oil. Other oils can gum up the machine.

A clean and oiled machine runs smoother, helps maintain tension balance, and makes thread breakage sewing and skipping stitches sewing less likely.

Frequently Asked Questions (FAQ)

h4. What is the best tension setting number?

There is no single “best” number. The right setting depends on your machine, the type of thread, the needle, and especially the fabric you are sewing. A common starting point might be around 4 or 5 on a dial numbered 0-9, but you must test on your fabric to find the perfect setting.

h4. My top stitch looks perfect, but the bottom has loops. Is that upper or bobbin tension?

Loops on the bottom usually mean the bobbin thread is too loose relative to the top thread. This can be because the bobbin tension is truly too loose, OR more commonly, because the upper thread tension is too tight and is pulling the loose bobbin thread up. Start by loosening the upper tension slightly. If that doesn’t work (and you have a removable bobbin case), then check and possibly tighten the bobbin tension screw a tiny bit.

h4. My bobbin case doesn’t have a screw. How do I adjust bobbin tension?

If you have a drop-in bobbin or a case without an adjustment screw, the bobbin tension is often factory set and not meant for user adjustment. In these cases, sewing machine tension problems causing bottom loops are almost always fixed by correctly setting the upper tension, ensuring the machine is clean, threaded properly, and using a good bobbin (wound evenly, inserted correctly). If problems persist, the machine may need service.

h4. How often should I check my tension?

You should check your tension any time you start a new project, change fabric, change thread type, or change needle size. Always sew a test sample on your fabric before starting your main seam.

h4. Can lint really cause tension problems?

Yes! Lint stuck in the upper tension discs stops them from gripping the thread evenly. Lint in the bobbin case or under the needle plate can stop the thread from moving smoothly as stitches are formed. Cleaning is a key part of fixing and preventing tension issues.

h4. My thread keeps breaking. Is it tension?

It can be! If your tension is much too tight, the thread can snap. But thread breaking is also often caused by a bad needle, using poor quality or old thread, the machine needing cleaning or oil, or the thread path being blocked. Check these other things along with your tension.

Fixing sewing machine tension is a skill every sewer can learn. It takes a little patience and practice. By checking your test stitches and making small adjustments to the upper tension first, you can solve most problems. Remember to keep your machine clean and use good needles and thread. With these steps, you’ll be sewing perfect stitches in no time!