I went to the library today to check out some new quilting books, but I took a detour while there and found myself in the sewing machine section. I discovered that my library has a wonderful book called Sincere's Sewing Machine Service Book by William Ewers, printed 1968. I haven't read the entire book yet, but this book is an excellent reference book. Chapters are dedicated to the long shuttle, class 15 oscillator, class 66 oscillator, the White Rotary, manual zig zag, the automatic zig zag, some miscellaneous machines, electrical equipment, attachments, service tips, and trouble-shooting guide. I suggest hunting this valuable book down if you haven't read it already.