Needle Info
Kay Lancaster
Singer doesn't use these designations, just the ball/regular ones.
(BTW, Singer needles often don't work in a European/Asian machine well, and Schmetz don't work well in many Singers. Slightly different needle lengths = miserably skipped stitches.)
Needle sizes are numeric:
70/10 for lightweight stuff like crepe de chine, batiste,
light rayons
80/12 for velveteen, cotton twill and similar medium weights
100/16 for denim, upholstery
120/18 for really heavy upholstery, luggage, shoes.
If you use too thin a needle, it tends to break and also to cause thread weakening. Too thick a needle usually leads to puckery seams and holes along the seamline.
Schmetz puts out a small brochure of needle types and sizes and uses, but I've only seen them at good sewing machine dealers, rarely at fabric stores. Duh.
BTW, I've started color coding my machine needles by type and size with all those wierd colors of fingernail polish. Just a dab on the shank of the needle just below where it will enter the machine. Dead needles (which I use for ripping, quite often) have the fingernail polish removed.