Originally Posted by
KwiltyKahy
You are right, it is a side cutter. Back in the day, Brother advertised that they had a sewing/serger combo. This attachment was the "serger" part.
That makes sense to me as you can clearly see the cutting blade attached to this piece. I knew it had something to do with serging because I could see the blade but it's so big that I can't quite picture it on the machine. Maybe the pic makes it look bigger than it actually is. Tks for finding out what it is though & letting us know. Curiosity gets me every time.