How a stitch is formed. Understand skipping stitches and shredding on a longarm machine.

Shredding Thread, Skipped Stitches and Stitch Formation - Explained

by Liz Holpin, Pinhole Quilting

There is nothing more frustrating than when you're quilting along and you find your thread is skipping stitches, the thread is shredding or breaking. It can really affect your quilting mojo! 

You check you thread and your needle and can't find out what is wrong.

So, let's look at what the components are of skipping, shredding and the longarm needle. We'll also consider some aspects of the thread and what might be happening there. 

We'll also cover Timing, Needles and in particular the High Speed or MR Needles. We hope that with this knowledge you will be able to analyse what is happening with your machine and fix your skipped stitches with less frustration so that you can get on and quilt!

This information is for Handi Quilter machines. Much of this content is taken from the Technical Guidance notes written by Glen Salter at Handi Quilter Technical Support and is copyright. It is not to be used by others or copied in whole or in part without permission.

How a Stitch is formed

Firstly, you need to understand how a stitch is formed. Consider that even on the slowest Handi Quilter machine this happens 1800 times a minute. On the fastest machine it happens 3100 times a minute!

The stitch is formed using the principal of friction. 

When the threaded needle reaches bottom dead-centre the thread is pinched against the back side of the needle above the scarf by the fabric. Bottom dead-centre or BDC is the technical term for the furthest the needle can possibly move when it is located in the correct position relative to the hook.

Cross-section of the hook and parts of the needle

The back side of the needle does not have a groove like the front side of the needle. The long groove in the front of the needle protects the thread from being pinched in the front by the fabric and allows a larger loop to form in the back of the needle for the hook to catch. At bottom dead centre, the hook has not yet arrived at the needle and the top thread loop has not yet been formed. When the needle rises or lifts a little, the loop begins to form. This distance which is called the Loop Lift is a specific distance on all Handi Quilter longarms of 2.2mm (it's slightly more on the Infinity - 2.6mm).  

The loop forms behind the scarf of the needle with the bottom of the loop at the needle eye, located below the scarf. At the same time that the rise or lift happens, the hook rotates so that it can enter and pick-up the created loop. 

You can see this happening in slow motion in the video from YouTube above.

If the hook misses the loop then a skipped stitch occurs. No loop no stitch! 

If this happens one time or more than once it is called skipping or skipped stitches. The top thread loop is pulled completely around the hook assembly basket, bobbin case and bobbin, wrapping the top thread around the bobbin thread and creating a lock stitch. This is like a half knot, wrapped once around each other. At the completion of the stich ideally this half knot will be located in between the two layers of fabric, making the strongest and nicest appearing stitch. 

Skipped Stitches

Skipping occurs when the hook misses the top thread loop on the backside of the needle. The needle will make an extra hole or holes in the fabric when this happens, but the stitch will be longer. This is sometimes, with a stitch regulation issue, because the results appear very similar. You can check to see which it is. If it's a stitch regulation issue you won't see any holes in the middle of the long stitch.  

Shredding 

Shredding occurs when the hook hits or collides with the top thread loop as the hook passes the needle or when something else abrades the thread, such as damaged thread guides. Thread can wear grooves into steel guides over time. It causes damage to the top thread until the thread shreds or breaks and then skipping occurs. 

Occasionally the thread will actually break and re-catch itself once again and sew further. The hook point is very sharp and will damage the thread when it hits it. This causes the thread to splay or fray apart and get hit even more until it breaks. It will sometimes tie different pieces of the thread into a knot in the take-up lever hole because the thread is going back and forth through it. Thread damage is often seen on the quilt top when this happens.

This is something I've often seen when I'm on classes and I'm called over to look at what has gone wrong with a customer's work. The machine has really got itself into knots. 

When we service machines we sometimes find thread wrapped around the inside of the parts of the machine which has entered the machine through the take-up lever which indicates that this has happened.

Causes of Skipping and Missed Stitches

So now you understand how the stitch is formed and why it might not form properly what can we do about it?

1. Change the Timing 

The "Timing" is the relationship between the needle and the hook and specific adjustments that affect timing. 

Anything that changes the relationship between the needle and the hook effectively changes the timing of the machine. When a needle is bent the timing of the machine changes. When the needle is installed incorrectly it changes timing. So, for example if you insert the needle so that it's at 7 o'clock instead of facing you at 6 o'clock you are changing the timing.

If you haven't had your machine serviced every two years there may be aspects of the machine inside such as the belt that need checking which means that the timing has changed. That is why we recommend having your machine serviced on a regular basis. If the timing belt  inside the machine is too loose it produces inconsistent differences between the hook and the needle. We check the timing belt tightness when we service your machine.

All of these items must be correct before the actual timing adjustments are performed. 

There are three primary timing adjustments, which are done after the machine has been cleaned, oiled, adjusted and has the correct needle position in the needle plate. 

These are loop lift, needle distance and needle bar height. More information is given regarding these adjustments and making sure the machine is healthy and ready to be timed in the service manuals for each machine. A qualified Handi Quilter service engineer such as our serviced engineers at Pinhole Quilting will be able to do this for you.

If you are outside of the UK we recommend you contact a qualified Handi Quilter technician.

Do not take your machine to a regular domestic sewing machine repair shop. Handi Quilter longarm machines use 6 different specialist oils and greases in specific parts of the machine. If you don't apply the right oils and greases your machine is not likely to last as long or perform as well. It may also affect your Warranty if it is still within the 5 year Handi Quilter Warranty.

2. Needle 

Use the correct needle system for the machine and size and point for the fabric and the thread. When a needle is used that is too large for the fabric and the thread, it will produce too big of a hole and friction is insufficient. This will affect the loop formation. Again - no loop, no stitch. If we add a slippery fabric to the above scenario it makes it even less likely for a proper loop to form. 

134 System R Point - Sharps Needle

On our Handi Quilter machines we use 134 needle system.

We have Sharps, Ballpoint, Multi Directions (MR) and Leather Needles from Groz Beckert and Schmetz. Schmetz and Groz Beckert are owned by the same parent company at the time of writing (October 2021).

Ballpoint (SES) - These are a LIGHT Ballpoint which we prefer for quilting fabrics

Leather Needles (Size 18) for Leather and Vinyl - S/NCR Point

Groz Beckert MR Sharps (R Point) Needles Size 19 4.5

The MR are defined as both the Metric size 19 and 4.5. These are a much stronger needle and I'll explain more about these below.

These are the same size needle but different types.

These pictures show how different needles look depending on the application.

The MR have a "crank" shank. It's a bend in the shank which presents the needle to the hook in a way which is designed to help with consistency, reduce thread breakage and perform better at high speeds.

• The needle must be installed all the way up into the needle bar. Double check it is by looking through the stop/sight hole. 
• The long groove and eye must be to the front with the scarf to the back, away from the user. 
• The needle must be straight and can be checked by rolling it on the needle plate. If the point wobbles, then the needle is bent and should be replaced. 
• The needle might be rotated slightly because of its round mounting shank and this may resolve skipping or shredding. 
• Conversely if the needle is not installed correctly this may also be the cause of skipping or shredding. 

3. Thread

Thread can be defined by its quality, size, type and twist. 

Quality thread is more consistent, stronger, and less likely to be the cause of problems. The thread should be appropriate for the application and fabric. If the thread is too big or too small for the needle it will cause issues with loop formation and skipping or shredding. 

Some threads can unwind during quilting making the thread easier to be hit by the hook point causing shredding and breaking. The direction of sewing can cause the thread to unwind in some cases. This unwinding can often be seen near the thread guides, the top tension disks, as well as the take-up lever. 

Always match the thread to the needle

4. Fabric

Fabric and issues relating to fabric can be defined in terms of thickness, density, type, height of the poles and tautness of fabric on the frame.

Some fabric is very densely woven and others very loosely woven. Keep in mind the principle of friction and how the loop is formed. The needle should match the fabric and the thread and be appropriate for the application. 

If the fabric is too tightly wound on the frame it can open the weave of the fabric even more, cause trampolining and skipped stitches or shredding. 

If the side arm pole supports are set too high the quilt will trampoline more and increase the chance of skipped stitches and shredding. 

Thread count of normal patchwork and quilting fabrics is normally 72 count. If you use Egyptian Cotton sheeting on your bed you might be familiar with a much higher thread count. Imagine the thread of a 40 weight, 3 ply cotton trying to squeeze through each hole of your Egyptian cotton sheets. If you use a very tight cotton sheeting on the back it's going to be very difficult for the machine to form a nice stitch at high speeds. If you get skipped stitches that might be why. Consider using patchwork weight fabric on the back of the quilt as well as the front. 

Batiks can vary in quality. The dyes and waxes used in the process can block up holes in the fabric and stop the progress of the needle and thread. Again, this can lead to skipped stitches.

5. Smoothness of Machine Movement

Consider moving too fast, too slow, jerky or erratic movements. 

When customers are new to longarming their movements tend to be less smooth and this can cause more thread breakages than more experienced customers. Try moving more smoothly and increasing speed gradually. Think of your longarm rather like doing a hill start with a manual car. You don't want to stall it! This is the equivalent of a thread break.

Moving the machine too jerky, fast, slow or erratic causes significant needle displacement, changing the relationship between the needle and the hook causing issues.

Try thinking of longarming as a whole body movement! It's not just about moving your arms.

6. Tension too tight - even though balanced.

If both tensions are too tight, the stitch may look great and the thread may not break, however, the thread may be pulling too tightly through the needle eye. This will displace the needle as the heavy quilting machine is moved around the quilt. This changes the relationship between the needle and the hook and therefore the timing. We have seen this cause skipping and shredding issues when all else is correct and the timing is adjusted perfectly.

7. Hopping Foot Too High

The hopping being set too high can cause poor loop formation, even at low speeds. 

Customers sometimes ask us about raising the hopping foot. We are reluctant to encourage this unless there is a good reason to do so. If we do, we recommend resetting it once a specific project has been done. If the hopping foot is too high the fabric can flag or trampoline up and down with the needle bar and the loop formation will not occur properly. This may happen at only slower speeds or not at all speeds. 

Sometimes customers may see the nut on the hopping foot or mount and adjust the hopping foot height for thicker quilts, not realizing they can simply push up on the spring-loaded presser bar to accommodate the quilt.

If you do adjust it or you've bought a seconduser machine and your foot is set too high and you use rulers the danger is that the ruler can slip underneath the presser foot with unfortunate consequences and a potential need to re-timing of the machine.

We check the height when we service the machine and adjust it if necessary to the standard height.

8. Speed 

Speed (We have found that needle deflection occurs more at higher speeds) so for the newer model of Avante (2015 onwards), Amara, Fusion, Forte, Infinity and Capri this is more likely than the slower models.

Handi Quilter recommend the High Speed Needles (MR) when sewing 2000 SPM and faster. 

These needles minimize the needle deflection when the machine is pushed away from you. In this direction there is greatest capacity for having issues with skipped stitches.

High speed needles will work on any Handi Quilter machine; if the machine is adjusted correctly for regular needles it will also work well with a high speed needle. If the machine is adjusted a little incorrectly then the issue may be magnified with high speed needles. 

The High Speed (MR Needle) - Let's Get to the Point!

The fastest machine in the Handi Quilter range is the Handi Quilter Infinity. Not only is it a 26" throat space machine but it has a speed of 3100 stitches per minute. 

The reason it can stitch at that speed is that as with ALL the Handi Quilter longarm machines they use an INDUSTRIAL machine needle. 

Why use an Industrial needle? 

1) The Round Shank is stronger because it does not have a ground flat section. If you look at your domestic needle you'll see it has a flat section. This weakens the needle.

2) The round shank means we can rotate it slightly and adjust how it presents to the hook. The customer can therefore adjust the timing slightly and this, as we explained above slightly adjusts the timing, getting around the problem of the timing being slightly out without having to adjust the hook position. 

Not all Longarm Machine manufacturers use Industrial machine needles. Some use domestic machine needles. In addition, domestic needles have a limit to the speed at which they can be run which is lower than the industrial needles - typically 2,200 will be the most that can be achieved. While speed isn't necessarily the most important factor for quilting your quilt some quilters may be frustrated by the limitations that this brings when they become more proficient. Longarm machines often have a speed limiter which will make a beeping sound when you are over-running the speed of the machine. 

The speed limiter will tell you when the speed you have set the machine at is impossible to achieve. For example you may have set the machine to stitch at 10 stitches per inch, but the speed that the machine can stitch at and the speed you are moving the machine over the frame on the carriage is so fast that your stitches will be longer than 10 stitches per inch. In this case you either need to slow down or change your stitch length to longer than 10 spi. (Or put up with irregular stitches and the machine making an annoying beeping noise!!)

The Infinity is shipped with the MR needle which is a needle specifically designed for multi directional use. Multi direction is exactly what we are doing when we are doing free motion quilting.

All the Handi Quilter machines can use the MR needle.

However, as stated above if there is a problem with the machine, the MR needle will not necessarily solve the problem! However, if your Handi Quilter machine is set up correctly it will give high reliability when stitching in multi directions.

Special Features of the MR Needle

Stability

The MR needle resists deflection and is very stable over the whole range of the needle due to its specially designed point and scarf. 

Stability - Copyright Groz Beckert

Protection of Thread

The thread groove extends all the way to the eye to protect the thread to minimise damage to the thread. The scarf design allows the loop to stay close to the needle to minimise damage as well.

Protection of the thread - Copyright Groz Beckert

Penetration at Eye Centre

When going through the quilt, the needle reaches its maximum force in the needle area. These forces increase disproportionally as the displacement cross-section increases. The MR needle was designed so that its penetration force in the eye area is less than that of a standard needle.

Displacement Impact - Copyright Groz Beckert

Thread Loading

When changing the quilting direction, the quilting thread is pulled out over the needle in all different directions. During its downward stroke, the needle slides along the tensioned quilting thread. This can result in changes in the thread twist, and consequently to negative loop formation. 

Multi Direction Needle - Copyright Groz Beckert

Loop Formation

The special asymmetrically shaped thread sliding area inside the eye of the MR needle guarantees stable loop formation even under unfavourable sewing conditions. This eliminates the possibility of unfavourable loop formation (*) and thread twist.

Loop Formation - Copyright Groz Beckert

Thread Pickup

Difficult sewing operations, such as quilting, can result in the thread unwinding during loop formation. The risk of unwinding is reduced by the special thread guiding of the MR needle. Its extreme scarf depth permits very tight hook point adjustment, resulting in optimum loop pick-up reliability.

We "time" the Handi Quilter machines so that the hook is just touching the needle to reduce the chances of having skipped stitches.If you are having problems with skipped stitches it may be worth trying an MR Needle. 

However, do discuss with us or email us if you are in the UK as it may be something else! 

Thread Pickup improvements with the MR Needle - Copyright Groz Beckert

Summary of the Benefits of the MR Needle

• Fewer skipped stitches 

• Less thread splicing 

• Less thread breakage 

• Optimal protection of the sewing fabric 

• High productivity thanks to reduced machine downtime - especially important if you're quilting for others

>> Buy Machine Needles on our Website

Servicing Your Machine

If you are in the UK and you would like your machine serviced please contact us.  We have a special Contact Form for servicing.  More details about servicing can be found on our Website - Pinhole Quilting Longarm Machine Servicing

Glen Salter from Handi Quilter Tech Solutions with our Handi Quilter Service Engineers Left to Right Back Row - Andy Soward, Derek Weir, Paul Pearce, Alan Harwood. Front Row - Pete Holpin, Glen Salter from Handi Quilter, Abigail Sheridan de Graaff, Liz Holpin.