Threads tangle up underneath if the stitch is not able to form correctly. The usual cause is incorrect threading; most often, the top thread, re-thread the machine with the presser foot up and the needle at the highest point. This will ensure that the tension disks are open and the check lever is in the correct position to take the thread easily. Your manual will show you all the guides that the thread will pass through. A video is available to show you the process; all sewing machines are the same basic principle; your machine manual will provide the details specific to your machine. Click Here

Skipped stitches are usually down to a damaged or incorrect needle type or size.
Changing your machine's needle needs to be done at least every 6-8 hours of sewing!
For general use, universal needles in sizes 60-120 are available. These needles are a bit ballpoint (used for knits) and a bit sharp (used for a woven fabric). We recommend changing your needle according to the type and weight of the fabric (and thread) you are using. Schmetz has an information booklet that you may find helpful. Click Here

Provided the feed dogs are engaged (worth checking) and moving correctly, the most likely cause is that the needle has a barb or hook on the point preventing the machine feeding the fabric through. You need to change your needle regularly (every 6-8 hours) and ensure that they are fully inserted with the 'flat to the back' (most modern machines).

Another cause can be the needle breaking and there are snags on the needle plate or presser foot.

Have you cleaned under your needleplate? It is possible the feed dogs are so clogged with lint and unable to move.

Shredding can be caused by the thread being caught around the spool, making it unable to flow freely through the top threading path.
If you have eliminated catching, then the following likely reason is the incorrect needle size for the thread or a damaged eye on the needle. Change your needle, ensuring the type and size matches your fabric and thread.

This is the most frustrating part of sewing with a sewing machine but is easily rectified when you know how!
When you finish a row of stitching, ensure that the needle stop is in the up position if your machine has the facility, this ensures the machine has completed the whole stitch and ready to begin a new one. The check-lever needs to be at the highest point too. If you have a machine that requires you to raise the needle by turning the handwheel, make sure you turn it until the check lever is also at the highest point.
Taa Daa!
No more unthreaded needles!

Alternatively you can remember to keep hold of the threads for the first few stitches every seam.

Tension! the biggest fear of many machine owners sewing life. Tension is the cumulative pull on the thread as it travels to form the stitch.

There should be very little reason to adjust tensions on your machine if it is in good working order, has been threaded with the presser foot up (so the tension disk is open to seat the thread correctly) and has the correct stitch setting, threads and needle for the fabric you are using.

Your machine is probably configured to sew with a 50wt cotton or 60wt polyester thread and a size 80/12 universal needle and sewn on a medium weight cotton or calico. replicating this

is the easiest way to check your tension.

Use contrasting colours top and bottom and see how the machine sews in a straight stitch and a zig zag stitch.

Bottom colour showing on the top is too high a tension on top so lower the number to 3-4.

Top colour showing on the underneath so raise the number to 5-6.

If you are constructing a garment, cushion, curtains or a quilt you need to be using the same thread top and bottom to have a quality stitch that locks you seams properly.

When you want to do quilting or decorative stitches and use different weight of threads in the bobbin you may need to either loosen the top tension OR tighten the bobbin tension*.

Many machines have special 'high tension' bobbin cases or the ability to increase the bobbin thread tension by a set amount.

* We do not recommend 'fiddling' with bobbin case tension unless you are using a spare. (Your service engineer may have taken a lot of time to balance your bobbin tension perfectly.)

When winding a bobbin you need to re-thread the machine in a different way, it will need to go through a series of guides and a pre-set tension disk, if you have skipped this or not seated it in the 'disk' you can end up with a loopy bobbin. Refer to your manual for the correct method.

If you have pyramid shapes this is something your engineer should be able to address at your service, in the meantime guide the thread as you wind with your finger. a gentle pressure up and down should persuade your bobbin to wind evenly.

Just because a needle isn't broken don't assume it is useable!

Needles need to be changed to match the type of work you are doing. In relation to the cost of the fabric and threads you are using the needle is relatively negligible in the cost but can ruin the work if burred or bent.

We recommend changing a needle every 6-8 hours of stitching, certainly at the start of a new project. A needle works hard penetrating the fibres at speed pulling the the thread in and out for miles.
Learn to listen to your machine you will hear a pop as the needle blunts.

If in doubt change the needle!

If your needles are breaking and you are using the correct size and type for your fabric let's check out a few of the possible reasons.

Is the needle fully placed as far up as it can go in the needle holder with the flat to the back?

Are you 'helping' the fabric to feed through the machine?

Is your flatbed/extension table on and supporting the weight of your work?

Are you removing pins before the needle hits them? This is more likely if the pins have flat heads and are unable to rotate and allow the needle to deflect.

If you are moving over thick seams? Use the Height Compensating Tool to keep the presser foot level.

Chrome needles are built to sew faster and longer. Modern high performance machines can sew up to 1000 stitches per minute. This generates heat in the needle as it penetrates the fabric repeatedly and the thread see-saws though the eye. (Even more so with manmade fibres.) Chrome needles stay cooler and with less friction in the eye and resistance to the the fabric.

Most domestic sewing machines require
the same system of needle with a flattened shank at the top and a shank with a
groove for the thread to travel to the eye, these are 130/750H. There
are several different categories of needles within this system, they differ in
size, needle point shape, and eye.

J, MIC, SUK, L etc. indicate the type of fabrics (or task) these
needles are intended for.

80/12, 90/14 etc is the diameter of the needle in two different
units, mm (80 =.8mm) and a numbering system recognised in the USA and Asia. Use
these numbers as a guide to the weight of thread and fabric they are suitable
to use with.

Your choice of needle is critical to the success of your project, the size and
shape of the point depends on the fabric you are sewing. There is a leaflet
that is very useful to help you choose. Click Here

Schmetz and Bernina needles use a colour code to identify the type and size of each needle. The top colour identifies the type, the lower the needle size. (Universal needles only indicate size.) There is a Colour Coding Chart you can download. Click Here

Most domestic sewing machines require the same system of needle that have a flattened top of the shank with a groove for the thread to travel to the eye. They also have a scarf on the back of the needle around the eye, these are 130/750H. There are several different categories of needles within this system, they differ in size, needle point shape, and eye.
J, MIC, SUK, L, S etc. indicate the type of fabrics (or task) these needles are intended for.
80/12, 90/14 is the diameter of the needle in two different units, mm (80 =.8mm) and a numbering system recognised in the USA and Aisa. Use these numbers as a guide to the weight of thread and fabric they are suitable to use with.
Your choice of needle is critical to the success of your project, the size and shape of the point depends on the fabric you are sewing. There is a leaflet that is very useful to help you choose. Click Here

Many overlockers especially those that cover stitch too, use a different system of needle to domestic sewing machines. It is advised to refer to the user manual to confirm the type of needles your overlocker uses.

This depends upon the type of machine. A simple rule is
that wherever there are moving metal parts that rub against each-other, they
must be lubricated. Cheaper machines may use plastic parts that may not need
lubrication, but most machines need the moving parts of the hook (shuttle)
lubricated with the correct oil to minimize wear and noise.

More often than you might think. We recommend
every 2-3 bobbins of thread or 6-8 hours of use, but it can depend upon the type of machine and what you are using it for. Listen to your machine, if it sounds noisy, it may be asking you to clean & oil it.

Don’t forget to remove the stitch plate and clean the fluff from under it. Never ever blow
fluff out of your machine because this can cause parts to rust from the moisture in your breath. Importantly, though, you should find out how to
properly clean and oil the hook, hook race and any other user-maintained parts of the machine regularly; you will find the machine will run quieter, last longer and produce a better stitch quality if you do.

We have a range of cleaning and oiling products for maintenance. Click Here

Always use a good-quality sewing machine oil and try to use the oil recommended by or supplied by the manufacturer wherever
possible. Never use DIY store or vehicle lubricants like, for example,
‘3-in-one’ or ‘WD40’ etc and never use spray lubricants – these can actually damage your machine.

This depends upon the type and usage of the machine, however, we recommend having your machine professionally serviced every 3 years. Many modern machines keep a tally on the number of stitches you’ve done and will warn you if it thinks it needs a service. Some old machines have the ability for you to oil the mechanism yourself but you should still have the machine properly cleaned, oiled and adjusted regularly to get the best out of it. Be aware, also, that some manufacturers warranties require the machine to be serviced at specific intervals in order to maintain the warranty, so you should always check your user manual for manufacturers recommendations on maintenance and servicing.

This usually requires that the machine’s mechanics have been thoroughly cleaned, re-lubricated with the correct lubricants and properly adjusted to manufacturers specifications using the correct tools. Where appropriate, the machine’s firmware should be updated to the latest version and all the functions should be checked and made to work, whether-or-not you use them.

This is a difficult question to answer because the majority of proper servicing goes-on inside the covers of your machine where you can’t see it. We recommend you try to talk to the service engineer before you hand it over – if he/she is negative about servicing your machine, find someone else! Following a professional service, your machine should sew correctly in all the modes and patterns it is supposed to and really, you ought to notice a significant improvement in the way it sounds, feels, and sews than before you sent it for service. Your machine should come back with a comprehensive sew-off sample showing a comprehensive set of its stitches. If you are at all unhappy about your machine after getting it back, don’t hesitate to take the matter up with the service engineer.

Threads tangle up underneath if the stitch is not able to form
correctly. The usual cause is incorrect threading; most often the top thread, re-thread the machine with the presser foot up and the needle at the highest point. This will ensure that the tension disks are open and the check lever is in the correct position to take the thread easily. If you have a front loading bobbin case the bobbin needs to rotate clockwise in the bobbin case. Top loading machines require the bobbin to rotate anticlockwise. A video
is available to show you the process; all machines are the same basic principle; your machine manual will provide the details specific to your machine. Click Here

This is the most frustrating part of sewing with a sewing machine but is easily rectified when you know how! When you finish a row of stitching, use the needle up button or the kick back function on your foot control. This means you have completed a whole stitch and ready to begin a new one.
Taa Daa!
No more unthreaded needles!
Alternatively, you can remember to keep hold of the threads for the first few stitches every seam.

You need to support the fabric with some stabiliser, (Stitch n' Tear or ordinary typing paper work well to start with) so that when the machine forms the stitch the thread is not able to drag the the fabric upwards. A zig zag foot with more surface area underneath is helpful here but a satin stitch foot is easier to see your stitches and has more room for any bulk created with your thread so a choice has to be made.

We love the wide stitches that our machines give us; beautiful alphabets and sideways stitches but when we want to have a perfect straight stitch we could end up wishing for Grandma's old treadle! This is a common dilemma with 9mm machines but it affects all zig zag machines, it is always easy to correct, when you know how!
If you are straight stitching and using very fine fabric, change to a straight stitch needleplate, (and foot) it makes a huge difference to stitch quality as well as preventing the machine gobbling your fabric.
There is an horizontal line on your needleplate showing you where to place the fabric to prevent fabric collapse, it is just behind the needle.
If you are dressmaking we recommend 5.5mm feet and a 5.5mm needleplate when you are doing anything other than a straight stitch.
When you are patchwork piecing, topstitching, quilting or free motion quilting, we recommend a straight stitch needleplate as well as you patchwork foot.
For safety, remember to use the security settings if available on your model.

Check that the thread is being delivered to the machine correctly. Cross wound and straight wound spools need to use different spool pins. Cones need a cone holder to ensure a smooth journey to the needle.

Is your needle the correct size for the thread you are using?

Is the thread suspect? How old is your thread, older cotton threads can go brittle with age, these need consigning to the recycle bin or make a beautiful display with the rest of grandma's sewing tools.
Re-thread your machine with presser foot up, a new needle that matches your thread weight and away you will go!