Joe,
In summary, If the needles is in front of me I measure and use the chart you provided. Simple takes about 10 seconds If the needle is not handy to measure and the number is unfamiliar I dig out the charts which vary by needle manufacturer and there are boat loads of them and often contradict one another.
Jon
PS--i use the cheap $10 harbor freight digital calipers even if I have 100 needles to measure and say unmarked. If say the needle is marked W&W 3 I'd measure one and use a loupe for the rest once the number is figured out. Measurements trump the charts and no micrometers or dial calipers fer me. This is only for size and assume the needle is known for instance 127x1, Davis Long, 15x1.
Last edited by jlhmnj; 12-28-2014 at 10:04 AM.