HERE IS SOME ANSWERS TO QUESTIONS ABOUT THE NEEDLE SIZE & THREAD TO USE WITH 
YOUR SINGER 306, 319 AND SIMILAR Machines Where can I get a chart for 319w 
needle size and thread size?
 thank you,
 duane
Dear Mr. Sechser,

Thank you for writing Singer. This household machine uses standard Singer
needles. You can use a 2020 for woven fabrics and a 2045 for knits. Most
commonly used size is a 14 for medium weight. Lighter fabrics could use
either a 9 or 11. Denim uses size 16.

Please use general purpose weight thread. This type of thread is available
at chain retailers such as Hancocks and JoAnn Fabrics as well as your local
sewing retailer. Make sure not to use quilting weight threads in the
machine as it will effect the tension.

Singer Consumer Affairs Department

SVP Worldwide