Bobbin Capacity | How Much Thread Does My Bobbin Hold?

How much thread does my bobbin hold? There is a major difference between a self-wound bobbin and a professionally wound prewound bobbin. Even among self-wound bobbins, there will be differences due to machine winding tension settings, speed, and size of thread. Here are estimates:

L style Bobbin
Bottom Line: 102 yds.
Masterpiece: 73 yds.
Brand X cotton: 39 yds.
So Fine: 66 yds.

M style bobbin
Bottom Line: 186 yds.

Masterpiece: 133 yds.
Brand X cotton: 71 yds.
So Fine: 120 yds.

Bobbin Tension

We often talk about the importance of tension adjustments when using specialty threads. Remember the illustration showing the tug-of-war between the upper and lower threads? The illustrations is at the bottom of the page.

Tension adjustments are usually made for the upper thread in order to allow the machine to run decorative threads. There are times, however, when it may be necessary to make adjustments to the bobbin tension. If you use a very fine and smooth thread in the bobbin, you may need to tighten the bobbin tension. If you use a very heavy thread in the bobbin, you may need to loosen the bobbin tension. The safest way to handle this is to have two bobbin cases, one for regular use which is not adjusted and one for specialty uses when can be adjusted.

Before making any adjustments, mark the normal position of the screw by making a dot with a permanent marker. Adjusting the bobbin tension is done by turning the small screw on the bobbin case. To loosen, turn to the left or counter-clockwise. To tighten, turn to the right or clockwise. Think of the adjustment screw as a clock and adjust the tension in the amount what would be a 5 or 10 minute movement on a clock.

Check the bobbin tension by using the drop test, which is the best way to know when the tension is right. Hold the end of thread and let the bobbin and bobbin case drop. It should fall approximately four inches and then stop. If it continues to fall, the tension is too loose. If it doesn't fall at all, the tension is too tight. If the tension is too loose, another problem called backlash may occur. This is when the bobbin thread continues to unwind unchecked, even after the sewing has stopped. The loose thread then gathers in the bobbin area or under the plate and tangles, resulting in breakage and bird nesting. By adequately tightening the bobbin tension, this problem can be avoided. Adjustments are simple. Learn to make the adjustments and you will be able to use a larger variety of threads.

Bobbin Tension | How And Why Tension Is Adjusted

The Other 10%
We talk a lot about tension settings and tension adjustments on machines. 90% of the time, we adjust the top tension to achieve the perfect stitch. This time, we will discuss the other 10%, the bobbin tension. Many have been told to never touch the bobbin tension. It isn't as difficult as we have been led to believe. If you are one who has been told to never touch it, by the end of this page, hopefully you will realize that is perfectly safe and easy to adjust the bobbin case. Of course you could buy a second bobbin case, one to never adjust and the other to experiment with, but why not save $30 to $40 and learn how easy and safe it really is. Over time, tensions can change with regular use. Even though you haven't physically changed the settings, they can work themselves either tighter or looser. Thread, lint, and even temperature can affect them. There are three times when adjusting the bobbin tension might be necessary. Number one and two are obvious. Number three is the "I never thought of that before" alternative.

1. When using a very smooth, fine bobbin thread. If the thread is very smooth and fine, the preset setting may not apply the necessary brakes to stop it when you stop sewing. In this case, the bobbin thread continues to unwind, causing backlash, and upon startup again, the thread will break. Tightening the tension will fix this. Think of a clock as you turn the screw on the bobbin case, turning the screw equivalent to a 5 or 10 minute movement. Right is tight. Left is loose.

2. When using a very heavy bobbin thread. The preset tension might be too tight for a heavy thread, preventing the bobbin thread from unwinding freely. Loosening the bobbin tension will solve this.

3. There are times when the bobbin adjustment is correct but no matter what I do to the top tension, I still can't get a perfect stitch or the thread breaks. When I loosen the top tension adequately low to run a sensitive or heavier thread, I get loops on the back. When I tighten up the top tension to get rid of the looping, the thread breaks. Looping on the back means the top tension is too loose compared to the bobbin tension so the bobbin thread is pulling too much top thread underneath. By tightening the top tension, the loops will stop, but the added tension may cause breakage, especially with sensitive threads. In this case, it might be necessary to loosen both the bobbin tension AND the upper tension. By loosening both the top and bobbin tensions, both sides of the tug-of-war give in, allowing a good stitch without breaking or looping.

Bobbin Threads Part 2 | Top And Bottom Thread Compatibility

Sewing machines are factory preset to have the top and bottom thread form even stitches. If the top and bottom threads are identical in fiber and weight, adjustments should not be necessary. However, if we use cotton on top and poly underneath, or metallic on top and poly underneath, or a heavy thread on top and a thin thread underneath, it is necessary to adjust the tension settings. It is fine to use different thread types and weights on the top and bottom.

Think of the top and bottom thread as having a tug of war. If the threads are identical and you are sewing on a single layer of fabric, both sides have equal strength and the result will be a draw. The sewing should therefore produce perfectly even stitches with no top thread showing underneath and no bobbin thread showing on top. However, in the real world, the teams are rarely equal. One team will be stronger or bigger or faster than the other. We use decorative threads on top. We often use different fibers for the top and bottom threads. We also add stabilizer or batting. Sometimes we might use a cotton bobbin thread and other times we use a polyester bobbin thread. All these factors make it necessary to adjust the tension for each project. By adjusting the top tension either up or down, we are able to add or take away strength on the top thread team to equalize the tug of war battle.
Following is a list of things that affect stitch results:

1. Batting. This adds drag on top thread. Cotton batting tends to grab the thread more than poly batting, adding more friction on the thread.

2. Fabric type. Dense fabric puts more stress on the thread.

3. Top thread thickness and type. Metallic is less flexible than cotton or poly. Poly is stronger than either cotton or rayon.

4. Bobbin thread type. Cotton bobbin thread tends to grab more than a smooth poly. Sometimes grabbing is preferred and sometimes it causes problems. A smooth poly thread (not spun poly) in the bobbin will work better with metallic or a heavier cotton and spun poly thread because it's silk-like finish acts almost like a lubricant, sliding nicely with the thread.

Prewounds
Approximately 70 percent of the home machines on the market are compatible with the standard L size prewound bobbin. The debate continues but the prewound users are winning. Although some machine dealers warn against using prewound bobbins, it is a fact that many of the educators on their staff do use them. The risk of prewounds is in the thread quality. Make sure you use a good quality thread and clean the bobbin area regularly. The advantage is in saving time and not having to wind your own bobbins. Prewound bobbins hold up to three times more thread than self-wound bobbins. Many prewound bobbins have cardboard sides which are removable. Some machines work best with the sides on, others work best with one or both sides removed.

Bobbin Threads | Pros And Cons Of Various Bobbin Threads

The pros and cons of various types of bobbin thread Bobbin thread is not always considered a factor when troubleshooting problems. Because the bobbin thread does not go through a needle, there are fewer problems with bobbin threads than with top threads. Most common bobbin threads are cotton, spun poly, cotton-wrapped poly, and filament poly.

1. Cotton. Quilters love it. It keeps the fiber content consistent with the fabric, batting, and top thread. For embroidery, it is OK, but on dense fill designs, cotton bobbin thread will result in a stiff design. Beware that lower quality cottons produce more lint which in turn requires more frequent machine cleaning. Choose a good quality bobbin thread.

2. Spun poly and cotton-wrapped poly. Stronger than cotton. Many machine quilters like this thread due to its strength. Like cotton, it does not have a slick surface and sometimes tends to grab the top thread too tightly creating uneven stitches and top thread breakage.

3. Filament poly. This thread has a shiny appearance and is virtually lint free. It can be thin and lightweight, yet strong. Embroiderers love this thread because it creates a soft backing, even on dense designs. Many machine quilters like using a filament poly thread in the bobbin. Due to its smooth surface, it works well with metallic threads and heavy cotton threads. The smoothness of the filament poly thread does not snag or grab the top thread. If you've had trouble using metallics or heavy cotton threads, a smooth bobbin thread may solve some problems. Examples of lint-free, smooth bobbin threads are The Bottom Line and So Fine.  

Bobbin University | All About Bobbins

1. Why are there cardboard-sided, plastic-sided, metal-sided bobbins?
It doesn't matter whether the bobbin is made of metal, plastic, or paper as long as there is sufficient strength to hold the thread. Plastic has improved over the years and is much less expensive than metal so most machine manufactures now offer plastic bobbins with their machines. Although most brands make their own plastic bobbins, 70% of machines now use the generic L size bobbin and it is not necessary to buy brand-specific bobbins. If your machine uses the L size bobbin, you can use either your machine brand bobbin or generic plastic or cardboard-sided bobbins. Pay more attention to the quality of thread on the bobbin than whether the bobbin is cardboard-sided or plastic or metal. Both the metal and plastic bobbins are reusable.

L-size cardboard-sided bobbins are the original standard. L-size plastic-sided bobbins have the same diameter and core size, but some are slightly taller. The advantage here is that it holds more thread. If the bobbin case is designed to hold a taller plastic bobbin and you want to use a paper-sided prewound bobbin because that has the thread you want, it will probably work but you may get some play or bounce in the bobbin. To correct this, stack one or two layers of the torn away cardboard sides underneath the bobbin to raise it up.

2. Should I remove the cardboard sides?

Do I need to remove the paper-sides on the cardboard-sided bobbins? The main reason to remove the cardboard sides is to allow machines with low bobbin thread warning light sensors to work. If your machine doesn't have a low bobbin thread sensor, there is no reason to remove the sides, so leave the sides on because it will usually fit better in the bobbin case. Machines are sometimes brought in for service because the low bobbin thread sensor no longer works. Sometimes it's as simple as making sure the bobbin cover door is closed during use so that the sensor light is aimed in the proper direction. If you sew with the bobbin cover open, your machine will work but the sensor will not. Some people prefer to turn off the auto sensor when using prewounds. A self-wound bobbin may have only a few feet of thread left when the bobbin sensor light comes on, so the warning must be heeded. However, for those who use prewound bobbins, the wind is usually much more compact and accurate and when the sensor beeps, there still might be 10 yds of thread left on the bobbin. If your machines stops at the low-thread warning, just turn off the low bobbin thread warning sensor and sew until it runs out.

3. Is there a top side and bottom side to a bobbin?

Yes, there is a top side. If your machine specifies that the thread needs to unwind with the bobbin rotating in a clockwise direction, hold a bobbin flat in your left hand and pull the end of the thread with your right hand, unwinding the bobbin. As you unwind the bobbin, the bobbin should rotate in a clockwise direction. If the bobbin is rotating counter-clockwise, turn it over and the direction will reverse. By properly placing the bobbin in the bobbin case, the bobbin system can work as designed. If you use machine-branded bobbins, the logo mark on the bobbin is usually the top side.

4. Why are there L-size, M-size, A-size, Class 15, and other brand-specific sizes?

Machine manufacturers make what they believe is the best bobbin for their respective machines. Some are made to fit only their machine and are not interchangeable with other machines, while others make a common bobbin type which is interchangeable with other machines. Some bobbins have holes in the sides. The advantage to this is that you can reuse a plastic-sided bobbin with holes because it is easier to get the wind started. If a bobbin type is exclusive to a specific machine, generic bobbins generally do not exist. Don't choose a new machine based only on the bobbin type, but if your machine uses one of the more popular sizes, you have an added bonus of being able to use prewound bobbins.

5. Are prewound bobbins OK to use in my machine? Will using them void my warranty?

Prewound bobbins are OK to use on your machine. The horror stories we hear about are not with the bobbin, but with the quality of thread. As with other products, there is large range of quality in bobbin thread. If you found a bargain on the Internet for a huge box of prewound bobbins for $9.00, you will probably get a very low quality, linty, loosely twisted thread that will do more harm than good. Although we often hear stories of customers being told that using prewounds will void their warranty, that is not true. That would be like saying using a low-octane gasoline will void your car warranty or using inexpensive film will void the camera warranty. The results will most likely not be what you wanted, but it won't void the warranty unless it is clearly stated in owner's manual or on the warranty card. By choosing good quality over fantastic Internet bargains, you will make sure your machine will operate as intended and stay in good condition.

6. Why use a colored bobbin thread?

A perfect stitch is sometimes hard to achieve and therefore the bobbin thread may show on top. A white or black bobbin thread is high contrast and therefore can be visible. By matching the color of the bobbin thread to the top thread, the bobbin thread will blend. Then, if the bobbin thread does show a little on top, it will not be visible.

Can I Touch The Bobbin Tension? | Reasoning For Adjusting Bobbin Tension

Golden Retrievers and Dalmatians

Getting the perfect stitch is the goal of all sewing. It is fine to use different threads in the top and the bottom, whether they be different fiber types (for example, cotton and polyester) or different thicknesses. Adjustments for these differences are made with the tension settings, usually to the top tension, but occasionally to the bobbin.

Machines differ in tension settings from brand to brand. Some machines are like calm, loving Golden Retrievers - very eager to please and they love everything we do. Other machines are like high-strung Dalmatians, requiring lots of attention and extra training. Most machines are somewhere in the middle. Even within brands, there is some variance from machine to machine. Just like a dog, if we learn how to train or adjust the machine, it will serve us well and bring much happiness. An untrained machine (and dog) can cause more frustration than joy.

If you have experienced problems running decorative threads and have adjusted the top tension every possible way and still cannot get good results, the solution might lie in the bobbin tension setting. For example, if the top thread is breaking because the top tension is too tight, it is necessary to loosen it. If you loosen it to the point where the thread does not break, but the top thread then loops on the back, the top tension is now too loose. This is a common problem with some longarm machines. Neither of these solutions work and adjusting the tension settings in between these two extremes doesn't work so what can we do? The problem is that the top tension and bottom tension are too far out of sync so no matter what we do to the top tension, it will not solve the problem.

In order to fix this, we must loosen the bobbin tension. Many of us were taught to NEVER touch the bobbin tension. That was when thread choices were very limited and decorative threads hadn't yet been invented or used on high speed and longarm machines. Times have changed. If you can thread a sewing machine, you can adjust the bobbin tension. There is no need to spend money on a second bobbin case. With a permanent marker, put a dot where the tension screw is now pointing to so you can always return to the original setting. Then, with a screwdriver and thinking of a clock, make adjustments by turning the screw equivalent to what a 10-15 minute movement would be. Counterclockwise loosens the tension (the most commonly required adjustment) and clockwise tightens the tension. Remember, lefty loosey, righty tighty.

For longarm machines, the bobbin tension should be loose enough that if you hold the bobbin case in your left hand and pull the thread up with your right hand, the bobbin case should not lift off your left hand. The old "4 inch drop test" is gone.

Now, after having loosened the bobbin tension, any adjustments you make to the top tension will be more effective because the top and bottom tensions are more in sync. You should be able to pull the thread through the needle fairly easily without feeling much tension.

Gammill Tension Adjustments | Adjusting Tension Settings For Decorative Threads

If you have experienced problems running decorative threads and have adjusted the top tension every possible way and still cannot get good results, the solution might lie in the bobbin tension setting. For example, if the top thread is breaking because the top tension is too tight, it is necessary to loosen it. If you loosen it to the point where the thread does not break, but the top thread then loops on the back, the top tension is now too loose. Neither of these solutions work and adjusting the tension settings in between these two extremes doesn?t work so what can we do?

The problem is that the top tension and bottom tension are too far out of sync so no matter what we do to the top tension, it will not solve the problem. In order to fix this, we must loosen the bobbin tension.

Many of us were taught to NEVER touch the bobbin tension. That was when thread choices were very limited and decorative threads hadn?t yet been invented or used on high speed and longarm machines. Times have changed. If you can thread a sewing machine, you can adjust the bobbin tension. There is no need to spend money on a second bobbin case. With a permanent marker, put a dot where the tension screw is now pointing to so you can always return to the original setting. Then, with a screwdriver and thinking of a clock, make adjustments by turning the screw equivalent to what a 10-15 minute movement would be. Counterclockwise loosens the tension (the most commonly required adjustment) and clockwise tightens the tension. Remember, lefty-loosey, righty-tighty.

The bobbin tension should be loose enough that if you hold the bobbin case in your left hand and pull the thread up with your right hand, the bobbin case should not lift off your left hand. The old "4 inch drop test" is gone.

Now, after having loosened the bobbin tension, any adjustments you make to the top tension will be more effective because the top and bottom tensions are more in sync. You should be able to pull the thread through the needle fairly easily without feeling much tension.

Gammills And Prewound Bobbins | How To Make Prewound Bobbins Run Smoothly

We tested our new SuperBOBs M style prewound bobbins on over 100 machines. 98% loved them; 2% didn't. With further testing and research, we have a solution for the 2%.

1. If the bobbin tension is too loose, the factory preset setting may not apply the necessary brakes to stop it when you stop sewing. In this case, the bobbin thread continues to unwind, causing backlash, and upon startup again, the thread will break. Tightening the tension will fix this. Think of a clock as you turn the screw on the bobbin case, turning the screw equivalent to a 5 or 10 minute movement. Right is tight. Left is loose.

2. If the bobbin tension is too tight, remove the thin, plate-like insert in the bottom of the bobbin case. This is called the bobbin brake or the anti-backlash spring. It is easily removed by lifting it out with a pair of tweezers. This will reduce the excess tension.

Prewound Bobbins Facts & Faqs | Frequently Asked Questions About Prewound Bobbins

Facts and FAQs (Frequently Asked Questions) about prewound bobbins.
1. Why should I use prewound bobbins when I can wind my own?
Good prewound bobbins are wound by high tech machines which provide a smooth, uniform wind. The result is much more thread on the bobbin than a self-wound bobbin. Whether you're in the middle of an embroidery design or a quilting or sewing project, having to stop to change the bobbin is always an inconvenience.

2. What does L style and M style mean?
These are the two most common sizes of prewound bobbins. Some longarm machines (A-1, Gammill, Handi Quilter, Homesteader, some Noltings) use the M size, which is the larger bobbin. Some longarm machines (APQS, some Noltings) use the L style bobbin. Approximately 75% of home machines use the L style. The trend is moving toward more compatibility as most home machine manufacturers are making their machines compatible with the L style bobbin.

3. Should I tear off the cardboard sides?
If the bobbin fit is too snug to accommodate free rotation, take off the cardboard sides. This will not affect the function of the bobbin. If your machine has an automatic bobbin sensor, leaving on the cardboard sides will make the sensor think the bobbin is always full and will therefore not provide a low bobbin warning. The solution is to either tear off the cardboard sides and use the sensor or to leave the sides on and sew until the bobbin thread runs out.

4. Is there a difference between plastic sided and cardboard sided bobbins?
Either type is fine. Plastic bobbins are reusable; cardboard bobbins are disposable. Because the plastic-sided bobbins are so smooth, they may continue to spin even after your machine stops and cause backlash. Some machines seem to work better with the cardboard-sided bobbins because the cardboard sides provide more friction and backlash is usually not a problem. If it is, the bobbin tension may need to be tightened.

5. Should I use a polyester or a cotton bobbin thread?
It's a matter of personal preference. Polyester has very little or no lint. Cotton prewound bobbins will throw off lint and will require more frequent machine cleaning.

6. My dealer told me not to use prewound bobbins. I've even heard they will void my warranty.
That's a myth. Today, almost all major machine companies sell prewound bobbins.

Problems? (Part 1) | Is It Me, The Thread, Or The Machine?

When I have problems using a particular thread, how can I tell if the problem is with the thread or with the machine?

Because there are many factors involved in sewing the perfect stitch, it is not always simple to find the cause when things don't go right. Here is a good place to star. Put the thread on a different machine. If you have another machine, try the thread on that one and see if it works. If you don't have another machine, try it on a friend's machine. If the thread runs fine on the other machine, then we know that the problem is with the first machine and not with the thread.

The first place to check is the needle. Make sure the needle is in good condition and is the right size. Remember, most decorative threads require a size 90/14 or larger. The topstitch needle is recommended.

The second place to check is the upper tension setting and tension area. When running decorative threads, the tension needs to be loosened. On a scale of 0 to 10 (with zero being no tension), loosen the tension all the way down between 1 and 2. If that is too loose, resulting in looping on the underside, ease back up slowly until you get the perfect stitch. Make sure the tension disk area is free of lint.

If you are running a metallic or a flat hologram thread, a smooth bobbin thread will work better than a linty bobbin thread. Cotton and spun poly threads are hairy or fuzzy. They can grab the top thread and that is OK for some top threads, but may not be OK for sensitive top threads. Hold a strand of thread up to the light and you can see which threads are more fuzzy. The small hairs come off in your machine as lint. All cotton and spun poly threads will have some degree of fuzz and cotton sheds more than poly. The higher the quality, the less fuzz. Filament polyester (not monofilament) threads are smooth and have no lint. Examples of smooth, lint-free filament threads are The Bottom Line, Rainbows, and Highlights, So Fine, Living Colors, Nature Colors, Art Studio Colors, and LAVA.

If a cotton or spun poly thread works well but a smooth filament polyester thread is breaking, the problem might be a burr. Smooth filament threads are more susceptible to needle burrs, lint buildup, snags, and rough spots in the thread path than are spun threads such as cotton and spun poly. Here's why: Remember when you had a rough fingernail that easily snagged nylons or other fabrics? It snags smooth fabrics such as nylon much easier than it snags on a cotton t-shirt. If a burr or a rough spot or a cluttered tension disk along the thread path snags a spun thread (cotton or spun poly), it will grab a piece of the thread and pull it out, creating a piece of lint, and the thread keeps on going, barely noticing that it lost a small piece of lint. However, on a smooth non-spun thread such as a filament poly or rayon, when a burr or rough spot or a cluttered tension disk snags a piece of the thread, there isn't a piece of lint to give and as a result, it may fray or break. You can save a lot of frustration by changing the needle every 6-8 hours of sewing time and by keeping your machine clean, and in good condition. Your sewing machine dealer can check for burrs.

Problems? (Part 2) | Troubleshooting Tips.

Troubleshooting helps

If you are experiencing trouble with broken threads or skipped stitches, the following may help.

1. Check the thread path from the spool or cone to the needle. Is it threaded correctly?

2. Is the needle in correctly? Is it square to the face of the machine? Is the scarf to the back? Are you using the correct needle? Is it inserted all the way?

3. Is the bobbin tension correct in relation to the top tension? Is the bobbin positioned correctly? Is there lint or other debris under the tension spring?

4. Is the top tension correct in relation to the bobbin tension?

5. Is the needle coming down in the center of the darning foot?

6. If a particular needle keeps breaking thread, do the following: Remove the thread and put it on a different machine. If the problem follows the spool of thread, you can assume the problem is a bad spool of thread. If the thread works fin on the second machine, the problem is with the first machine and not with the thread.

7. Change speed according to the job being done. As a general rule, the following will apply: The wider a satin stitch, the faster the machine can be run. The narrower a satin stitch, the slower the machine should be run. Compensate for slowing the machine down on small satin stitches by speeding it up on large satin stitches and fill stitches. There is nothing wrong with changing machine speed while running the same design. The speed control was put on the machine to do exactly that -- to change the speed in accordance to what you are running.

Determining tension problems

Tension is the term we give to the process of balancing the top and bottom threads so the machine will sew a good stitch.

Problem: The top thread frays.
Probable Cause: The needle is too small, the top tension is too tight, or there is a burr or rough in the thread path.

Problem: The bobbin thread shows through on the top.
Probable Cause: The bobbin tension is too loose, or the top tension is too tight.

Problem: The top thread loops on the bottom.
Probable Cause: The bobbin tension is too tight or the top tension is too loose.

Problem: The top thread snaps and leaves a small hook at the point of the break.
Probable Cause: The top thread is too tight.

Problem: The thread gathers under the needle plate.
Probable Cause: There are two reasons why thread gathers under the needle plate. Either the top tension is too low or the machine is threaded incorrectly, bypassing the take-up lever. It is not a thread problem. If the thread were inferior it would simply break and not be strong enough to gather under the needle plate and jam the machine. What is occurring is that when your take-up lever raises to pull the thread back up through the fabric and form the stitching knot, it is instead simply pulling thread off the spool because there is not sufficient top tension. This situation results when the tension is set too low, the tension disks are held apart by lint or thread debris or the thread is not pulled all the way down between the disks. The other condition occurs when the take-up lever is not pulling the thread back through at all because it is not threaded. Clean your machine regularly.

Thread Tug Of War | How Tension Works

Sewing machines ar

e factory preset to have the top and bottom thread form even stitches when sewing with a 50 or 60 wt. thread. If the top and bottom threads are identical in fiber and weight, adjustments may not be necessary. However, if we use cotton on top and poly underneath, or metallic on top and poly underneath, or a heavy thread on top and a fine thread underneath, it is necessary to adjust the tension settings. It is perfectly OK to use different thread types and weights on the top and bottom. Relying on a machine's automatic tension system is not enough.

Think of the top and bottom thread as having a tug of war. If the threads are identical and you are sewing on a single layer of fabric, both sides have equal strength and the result will be a draw. The sewing should therefore produce perfectly even stitches with no top thread showing underneath and no bobbin thread showing on top. However, in the real world, the teams are rarely equal. One team will be stronger or bigger or faster than the other. We sometimes use decorative or sensitive threads on top. We often use different fibers for the top and bottom threads. We also add stabilizer or batting. Sometimes we might use a cotton bobbin thread and other times we use a polyester bobbin thread. All these factors make it necessary to adjust the tension for each project. By adjusting the top tension either up or down, we are able to add or take away strength on the top thread team to equalize the tug of war battle. Following is a list of things that affect stitch results:

1. Batting. This adds drag on top thread. Cotton batting tends to grab the thread more than poly batting, adding more friction on the thread.

2. Fabric type. Dense fabric puts more stress on the thread.

3. Top thread thickness and type. Metallic is less flexible than cotton or poly. Poly is usually stronger than cotton or rayon.

4. Bobbin thread type. Cotton bobbin thread tends to grab more than a smooth filament polyester. Sometimes grabbing is preferred and sometimes it causes problems. A smooth filament poly thread (not spun poly) in the bobbin will work better with metallic and other sensitve threads because its smooth finish acts almost like a lubricant, sliding nicely with the thread.

used with permission from Bob Purcell. www.superiorthreads.com

tug of war diagram