I don't know either, but I wantedt to thank you for reminding me that I need to go dig out my serger which is in a box in the garage SOMEWHERE....I've never used it; it was my grandma's and when we moved, I threw a huge box of spools of thread away b/c I didn't want to drag it from place to place....now I regret that stupid move......I want to learn how to use it now
. But I suppose the first step is to unearth it!