Size of Needle
Choice of size is determined by the fabric and the thread combination which is to be sewn.
If needle is too small for the thread, the thread will neither pass freely through the eye nor fit properly into the long groove. As a result it will suffer from excessive abrasion. It may result in
Costly thread breakage in production because the machinist must stop to rethread the needle and possibly also to unpick some of the stitching so that a joint does not show in an important part of the garment.
When sewing heavy plies of material, a fine needle tend to get deflated. It can affect the stitch loop pick up and cause slip stitches, or it can even lead to needle breakage
A break in the situation of multi-needle sewing with fabric running through the folders would be impossible to repair.
If the needle is too large, there will be poor control of the loop formation which may cause slipped stitches.
There will also be holes in the fabric which are too big for the stitches and give an unattractive seam appearance.
In closely woven fabric, there will be a pucker along the seam line due to fabric distortion.
Nomenclature for Needle Size
Metric
d x 100 = Metric Number, where d is in millimeter,
eg. For d = 0.65 mm, number of needle is 0.65x100 =65
Selection of needle and thread size for a particular seaming situation is a question of achieving a balance between the minimum damage due to pucker which is a matter of small needle size and seam strength which requires a substantial needle and thread.
