Thanks Tammi for the link, there's some good information in the video. Learned that my Singer 1036 with the horizontal spool pin puts a twist to the thread. It was the only sewing machine that I owned until October '12. I haven't had to deal with spinning spools for over 30 years.
The spool is stack wound. I was zipping along pretty fast doing an edge finish to prevent raveling when I washed the fabric.