Needle Size Designations
In 1942, uniform needle sizes were fixed. A metric size designation under the abbreviation NM was introduced to replace the 40 or so different size designations in use at that time. This “Number metric” indicates the diameter of the needle blade in hundredths of a millimeter measured above the scarf or the short groove, but not at any reinforced part of the blade. A sewing machine needle with a blade diameter of 0.80 mm therefore corresponds to NM 80 and a needle with a blade diameter of 1.30 mm to NM 130.However, other size numbers are still in use today.
The comparison table below shows the corresponding needle sizes: