Class 15 machines can be low, high, or super high shank, and though it's generally true that most vintage machines are oscillators, horizontal rotary hooks can also be class 15. For example, most new machines now.
All "class 15" means is that it uses a class 15 bobbin. Class 66 machines use a 66 bobbin.
Cari
Last edited by Cari-in-Oly; 06-24-2017 at 11:47 AM.