I use pretty much whatever thread is handy and is a regular weight. Before I got one of those thread holders I used a large mouth Mason jar to hold my large spool of thread as my thread holders are horizontal and the thread kept catching on a rough spot on the spool. Just toss it in the jar and thread your machine as usual. Worked like a charm. My embroidery machine doesn't always like threads on a horizontal thread pin but worked fine on the spool holder or in a jar. Seemed to unwind more evenly. If you are having problems it's a cheap fix to try.