Yeah, I've found more who say the two are NOT interchangeable than who say they are. I am familiar with Helen Howe, but I will wait to see the condition of the shuttle which might come with the machine I thought I saw one winking out a little box in the photo). With a lot of patience, my tiny files, crocus cloth, and my hard Arkansas slip stone, I have gotten shuttle working before. Often the point is peened or chipped, but can be reformed. Tweaking the flattish springs is harder. We'll see.