If handed a gizmo or gadget and asked for my opinion, my first question would be, “Well, what is it suppose to do?”. Knowing the way something is designed to work is the first step to understanding how to make it work well. This month I decided to give a brief overview of the elements that work together to create a good stitch. The beauty of the sewing machine is that the basics of getting a great stitch are the same for the smallest sewing machines, feature filled embroidery system and longarm quilting machine. This anatomy of a good stitch includes the bottom thread, top thread, stitch mechanism timing and the sewing foot.

The Often Neglected Bobbin


The bobbin thread is an excellent place to begin. Unfortunately, the bobbin is like the proverbial “red headed step child”. Sewers become focused with the top thread tension to the point of ignoring the significance of how the underside is setup. The bottom stitch begins with a bobbin. In an ideal case, a bobbin is wound with firm even tension. There are no tails and no over filling of the bobbin. Should one use pre-wound bobbins or wind your own? The most basic issues that play into this are:

Do you wish to pay someone to wind your bobbins?
The color palette available to pre-wound bobbins will always be more limited.
Does the model and brand respond well to the paper, plastic or no-sided bobbins that most pre-wounds come in?
Winding bobbins in the studio will have less thread and more room for inconsistent winding.

Among various techniques and machines pre-wound bobbins can be blessing or a hinderance. The operator should not be afraid to test both option and simply go with what works for the situation. In the end, a good stitch will depend on a consistent and firm winding, regardless if the sewer or a factory does the winding.


Next is the bobbin case. A good stitch needs a clean bobbin with a consistent pull from the tensioning. All bobbins use a sort of pinching slot that lets out thread consistently, at a desired pull. This pull or tension is set by the factory in some cases, and in others the sewer or quilter can adjust according to the situation. If the bobbin tension screw is painted then it is set by the factory and the operator should leave it alone. In other cases, the operator should set tension so that it counters the pull of the top thread. A good stitch is adjusted for balance and not simply to make tension tighter. Many domestic models prefer a qualified technician set tensions. With most quilting machines the operator is expected to make this adjustment. There are two schools of thought on how to find this proper adjustment.

The weight of the bobbin and bobbin case should not be lifted out of the hand by pulling up on the thread, but the case can stand up. This takes a bit of time and finesse to learn how to gauge for thread thickness, weight and how much thread is on the bobbin.

There are tension gauges that allow an operator to see empirically the bobbin case pull. Setting tension to a mid level in the beginning allows the operator to have a comfortable starting value to adjust against, and it helps when working with technicians over the telephone. There are different sizes, so be sure to find the correct size for your sewing machine.

Regardless of the method used, a good stitch depends on a consistent and balanced tension to properly pull down on the top thread. Also, the method for setting tension must be consistently repeatable by the operator.

Moving To The Top



The top side of tensioning begins with the cone or spool of thread. It is tempting to base thread choice solely on color, without regard to the type or make of the thread. A good stitch is easier to reach with a stronger thread with less variance in the thickness along the strand. This uniformity will help in promoting a smooth thread flow and better stitch. Be aware of how the thread is wound. Most cones are cross-wound. This means the thread is designed to be pulled off the top. Spools, on the other hand, are wound straight and expect to be pull off directly from the side. Choose the correct style for the machine being used. One final consideration for a good stitch is the type of thread in relationship with the bobbin. The key to proper tension is balance. Balance is reached with greater ease if the thread used in the bobbin and on the top cone or spool are more similar - even identical. It is true that wildly different type of thread can be used, but it depends on the application and how much the operator is comfortable with tension adjustments.

Once the thread leaves the cone or spool, it is threaded through guides. A good stitch requires guides to keep the thread held along the threading path. If kept on this path, the thread avoids extra draw which can result in looping and other poor quality issues. A machine can have few or many guides. A good sewer always reviews the operation manual to ensure proper use of thread guides.

One of the keys to a good top tension is a concept called pre-tension. The longer the sewing arm, the more critical this becomes. Maintaining a firmness, or tautness, to the thread during it’s travel to the needle ensures that the tension devices work properly and that extra thread is not let out.



All sewing machines have some type of device or devices that provide primary tensioning for the top thread. The purpose of these devices is to control the amount of pressure it takes to draw top thread, so that when the stitch is made the bobbin and top pull is balanced, creating a level stitch. This tension is either a consistent draw or an intermittent draw. With consistent draw tension, a tension disc applies pressure to the thread via friction or counter rotation. In either case, a good stitch needs an even flow and consistency to this draw. Inspect the discs, washers, springs and other components for undue wear and debris. On many domestic models, these top tension devices are enclosed into the body of the machine so that a qualified technician will make any needed adjustments and cleaning. With an intermittent draw tension, pressure is applied to the top thread draw once in each stitch cycle. This “pinching” of the thread during the stitch helps keep the thread pulling from the bobbin case area instead of from the cone or spool. A good stitch is made when all of the thread let out during the cycle of the sewing hook is pulled back up to form the knot. Properly functioning intermittent tensions need to stroke, or “pinch”, the thread on the up stroke and it must stroke the proper distance.

The final aspect of the top tension devices is the check-spring. This paper-clip looking wire is usually associated with the main tension device, although many domestic machines separate them. This spring, in either case, needs pull firmly on the thread as well as have a long enough stroke to keep thread taught during the making of the knot. Consult the operation manual to see what types of devices are used in the machine, where they are located and what type of adjustments can be made. Remember that on some machines, these devices are not accessible to the operator and must be taken to a technician for service. However, the more industrial type machines - like longarm quilting - are designed for the operator to gain a comfortable familiarity with the adjustments.

In most cases, once the thread has left the tensioning devices it is pulled through a take up lever. This lever strokes at least several inches and is the primary method for pulling the stitch knot tight.

The end of the journey for the top thread flow is the needle eye. Wether the needle is threaded from the side or front, a good stitch needs the needle oriented correctly to ensure the hook can meet the needle at the correct position. Check and clean the needle cavity, and ensure the needle is inserted all the way into the needle bar. For some longarm machines there is a hole above the needle bar screw. This hole passes through the needle at the top of the needle cavity. As needles are changed, pass the old needle backwards through this hole to clean out any debris that may stop full needle insertion. Also, consult the thread manufacturer for proper needle size. A good stitch has the proper needle size to minimize thread friction.

Stitch Timing

After proper threading, a good stitch depends on proper timing of the sewing mechanisms. Stitch timing is comprised of needle-to-hook timing and positioning as well as thread escapement. As the threaded needle moves up from the lowest point, a hook travels pass the needle and catches the top thread. This sewing hook carries the thread completely around the bobbin. In a good stitch, this action is precisely timed to avoid missing the thread which results in a skipped stitch. This basic concept is the same for any rotary hook sewing machines, even for drop in bobbins. Fortunately this adjustment is a simple turning of the drive shaft or sewing hook to position properly. After the thread is pulled around the sewing hook, the thread must escape the hook area without getting caught. For smaller sewing hooks, this thread escapement is not an issue. For larger hooks, this can be a problem resulting in occasional looping. Some machines have a mechanism called a rocking finger, to open the thread escapement and avoid any thread catches. A good stitch needs the top thread to be caught by the sewing hook at the needle and pass around the hook unhindered. The top thread catches the bobbin thread at the fabric and secures the stitch. If the draw pressure is balanced, then the stitch is pulled evenly into the fabric.

Sewing Foot

While the needle is creating the stitch knot, the fabric must be held in place. The sewing foot applies pressure to the fabric. Machines with feed dogs pull the fabric along in a uniform direction and speed. Free motion feet hop up and down, “pinching” the fabric layers as the needle moves in and out. A good stitch needs the fabric held in place during the stitch, otherwise extra thread is pulled out by the fabric motion and is left as a slack loop.


Although some differences in adjustments exists between the difference types of   systems, all sewing machines operate by the same basic principles. The elements of a good stitch can be broken down and understood by any sewer. Knowing what the machines is suppose to do will help immensely when trying to find out why your stitch is not quite what you desire. This information is not exhaustive, but does cover the concepts and anatomy of a proper stitch. Next month I will continue with this concept by covering how the operator’s actions can effect the stitch quality as well as discussing the anatomy of a bad stitch.