The Anatomy of The Needle
The needle is primarily divided into two main parts—the shank, which is the thick portion that fits into the machine and the blade, which is a little over half the needle’s length. Each of these parts has other parts so let’s take a tour of the needle, starting at the top. You can follow along with the illustration to the right.
The butt is the end of the needle. It is inserted into the opening of the needle bar and pushed up against the top of the needle bar shaft. The shank is the thick portion of the needle at the top of the shaft, which is the long section containing a channel down the front, called the groove.
The groove is designed to hold the thread close to the needle from the machine to the eye. Keep it clean so it can do its job well. The width of the groove is only 40 percent of the width of the needle, which is why you are limited to the size of the thread for a particular needle if you want your embroidery to be a quality product with no rough edges or scruffy surface.
The scarf is the curved indentation above the eye on the back of the needle. It is also known as clearance above the eye (CAE) or the spot. The scarf faces the hook assembly and the point of the hook passes through that scooped out section to catch the loop of thread created during stitch formation. When timing your machine the degree of separation between the needle and the point of the hook places the that point just inside what would have been the back of the needle if there were no indentation—quite an engineering marvel.
The short groove is the name given to the area above the scarf on the back of the needle.
The taper or shoulder is the portion between the shank and the blade.
The blade is the working area of the needle. The diameter of the blade is measured in hundredths of millimeters, indicated by the metric number in the needle size notation.
A needle is a fine tool, and the blade can flex. If the flex is too great the needle will break. Flexed too far, and the needle will hit the throat plate, perhaps causing a burr or nick that will lead to exasperating thread breaks. Garments hooped too loosely can also cause the needle to flex—which goes to show—once again, how the entire process of our embroidery works together to create a quality product. Heavy garments, even if properly hooped, can cause a too thin needle to flex. Substantial garments call for the 80/12 needles.
The area on either side of the eye is the anvil (also called the stirrup.) This area is weaker in larger-eyed needles as there is less metal. Take this into consideration when matching needle to substrate.
The area around at the end of the needle is called the tip. It contains the eye, the hole at the end of the needle that accepts the thread. The eye can be small or large, oval or square. Needles that are polished inside the eye prevent fraying and thread breaks…buy them. They save many a headache. The eye carries the top thread through the fabric and into the bobbin assembly where the stitch is formed; it should be carefully engineered. The eye is smaller than the shank and is generally one-third of the blade, which leaves one-third of the metal on either side of the anvil to do the work. Add a large-eyed needle (less metal surrounding the eye) to a heavier fabric and you have catastrophe—a needle break—waiting to happen.
The point groove is the small indentation on the side of the needle that directs the thread to lie at a 90° angle from the eye. In smaller needles it can barely be seen. The size of the eye is matched to the size of the groove, which is there to hold the thread against the needle as it forms the loop on the backside of the fabric. Don’t neglect that last thread holder on the way to eye. Holding the thread against the needle cuts down on thread abrasion and resulting thread breaks.
The point is the area below the eye that enters the fabric first. When the point makes the hole, the shank widens it enough so the thread, enfolded by the groove on the front of the needle, can follow along behind easily. When the needle reaches its lowest point, the take-up lever releases the tension on the upper thread for just a moment so that the loop is formed behind the eye of the needle on the backside of the fabric. At the same time, the point of the bobbin hook rotates and catches the loop in that upper thread, pulling it down to join the bobbin thread. The needle then rises back up through the fabric and pulls the stitch tight. When the needle exits the face of the fabric, the hole that it creates closes back up—as much as possible—which is why it is important to keep the needle penetrations as small as possible