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Service Corner A GENERAL GUIDE TO SEWING MACHINE—THREAD & NEEDLE SIZING In general: Needle part names
STITCH LOOP FORMATION: The sewing thread diameter should be about 40% of the needle size for proper loop formation (condition #1). In this situation, the threaded needle penetrates the fabric being sewn and the thread will slip into the long front groove of the needle, reducing friction to a minimum as the thread goes through the fabric. The moment the scarf short grove is through the material, the thread on that side of the needle will automatically be jammed between the side of the needle and the fabric and will be kept taut until the needle has reached its lowest point. As the needle starts its return, the thread in the long groove can easily glide within the groove, but the thread on the opposite side will be retarded and will form a loop. At this point (usually after the needle has traveled upward (about 2-3 mm) the different shuttle or hook systems slip through the loop and join the top thread with the bottom thread. This is how stitches are formed.
DIAGRAM 1 (cross section view)
If the needle/thread condition #2 occurs, the thread is jammed on both sides of the needle resulting in poor loop formation. (It appears like a loose upper tension or looping on the bottom of the fabric) The extreme friction will cause skipped stitches, thread breakage and tension problems. In condition #3, where the thread is too thin, the sewing thread is uncontrolled and the loops become irregular. This results in faulty stitches and damage of sewing thread. (wavy appearance, etc.)
Common Thread Sizing Standards In the industrial sewing thread market, the Cotton Count System (NEc) has been the accepted standard utilized in sizing spun threads and the Denier System(Td) has been the accepted standard for filament threads. Over the last several years there has been a great deal of support to adopt an universal standard under which all sewing threads can be sized and will be understood world wide regardless of the thread’s construction. The TEX System is that standard for industrial sewing thread and allows you to relate the thread that one manufacturer calls number 50 to a 40/3 ply from another manufacturer.
THREAD SIZING SYSTEMS All threads can be produced in different thicknesses and the "size" of a particular thread is the relationship of its length to its weight. This relationship of length to weight is known as linear density, yarn count, or size. There are many sizing systems used, but they generally fall into two classifications: Fixed Weight These systems use the length of yarn that make up a given weight. NEc (Cotton Count) - For Spun Threads - This is the number of hanks (840 yds.) of yarn it takes to equal 1 pound. •A cotton count of “1” means 840 yards of yarn weigh 1 pound. •A cotton count of “2” means 1680 yards (840x2) weigh 1 pound. EXAMPLE: If you had a single strand of yarn 840 yards long weighing one pound, its count (or size) would be shown as 1/1. This simply means it had a count of one (the first number) and that it was a single strand of yard (the second number). If you then twisted two of those single strands together, the size would then be 1/2: One count yarn (the first number), in a two ply construction the second number). Equivalent Size The same size thread can be constructed using different count yarns by varying the number of plies. All the following threads are physically the same size. • 30/2 • 45/3 • 60/4 To determine the equivalent size, simply divide the yarn count by the number of plies. All three of these threads have the equivalent size of 15. IN FIXED WEIGHT SYSTEMS, THE HIGHER THE NUMBER - THE FINER THE YARN.
Thread Weight Another popular size measurement system, particularly embroidery thread is “Thread Weight”. Since most embroidery thread is a two-ply construction it is generally believed that “Thread Weight” equals the count number (the first number) as in the Cotton Count System. • 40/2 = 40 count, 2 ply = 40wt. • 30/2 = 30 count, 2 ply = 30wt. Unfortunately, this only works for two-ply threads. For example, a 40/3 quilting thread is not a 40wt. thread. 40/3 Cotton 40 ÷ 3= 13.33 equivalent . The same size in a two-ply thread would be 26.67 or a 26.67 weight.
Selecting the proper machine needle The relationship between needle and thread is crucial to successful sewing or quilting. As important as it is to select the proper needle for the fabric, it is equally important to select the proper needle for the thread you are using. Very often thread breakage, skipped stitches or other "thread" problems are the result of damaged or improper needle selection.
Proper needle selection is determined by two key factors: 1) the thread to be used and 2) the fabric to be sewn or quilted. • Select the thread to match the fabric or the project • Next, select the needle type best suited for the fabric used • Finally, select the needle size to match the thread. The thread must lay in the front groove without sitting on top or wobbling in the groove. The eye must be large enough for the thread to pass through with minimal friction in order to create a perfect stitch. • Always start with a new needle
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1276 Wellington Street West Ottawa, Ontario Canada K1Y 3A7
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SERVICE CORNER |
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NEEDLE – THREAD (SPUN) COMBINATION CHART |
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Needle Size |
Cotton Thread wt (2ply) |
Silk Thread |
Polyester Thread |
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Metric |
US |
Fabric |
Fabric |
Fabric |
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Light |
Medium |
Heavy |
Light |
Medium |
Heavy |
Light |
Medium |
Heavy |
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60 |
8 |
80 |
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