So I took some time out from my sewing machine & found a wealth of information online. I now feel 100% competent to choose my own needles & understand why I need each one. I KNOW I have used incorrect ones in the past & now that I am more aware of just how technical machine needles are, I can understand that using the right needle can severely increase the perfection of your project!
First up, let's look at the anatomy of a needle.
This picture comes from the (very informative) Schmetz website
This will be important when we look at what makes each needle unique.
Machine needles come in nine different sizes, and these are written either in US sizes (8, 9, 10, 11, 12, 14, 16, 18, 19) or in EU sizes (60, 65, 70, 75, 80, 90, 100, 110, 120) which is (I read on one of the many sites I visited) the diameter in fractions of a millimeter. The lower the number, the thinner the thread & the finer the fabric it is intended for. The higher numbers can be used with thicker threads and are meant for thicker fabrics.
Here is a useful chart from About.com
You should change your needle every 8-10 hours of sewing as the tip gets blunt and the blade can get slightly bent from hitting pins, thick seams, etc.
Two rules to bear in mind:
◦ The eye of the needle should be 40% larger than the diameter of the thread
◦ When going to a larger size of thread, a larger needle should be used
This number system works across the range of needles, so whether you are using a universal needle or a stretch needle, you still stick to this guide.
So what makes each type of needle different? Well, it turns out, each type of needle is adapted to its task! For example: a metallic needle has an elongated eye; a microtex needle has a very slim point; a denim needle has a modified medium ball point as well as a reinforced blade.
There are many specialized needles available, as well as one I only discovered today, which will really help people with trouble threading the needle. This amazing needle is called a quick threading/ handicap / self-threading / Öhrschlitz Needle. It has a small slit on one side of the eye, where the thread may be passed through instead of threading the thread through the eye! It cannot be used for all projects & only comes in size 80/12 and 90/14, but will help you where it can.
**NB: Read this to find out which projects you can use it on.
If you cannot use this needle on your project, and your machine does not have a built in threader, I would recommend this handy little gadget:
It is made by Elna and I bought it on US EBay here
I brought back 10 of the cheaper Bernina ones from S.A. for my sewing ladies, but have found them to be less than useless! The little metal bit inside bends to one side at the least provocation, and is only righted by careful coaxing back into place with tiny pliers (time consuming). So, learn from my mistake! Do not buy the cheap ones, they will not make you cheerful!
Above is a picture of the Bernina needle threader that you should AVOID!
I also discovered today that some needles are better than others for sewing a perfectly straight line. Not always the user fault after all! You can now blame the tools ;) Or rather just grab the correct needle & improve your lines.
Read this from the Schmetz guide: