Originally Posted by
nanjam62
Yes, I do have the needle plate...I found another plate that I think is used to cover the feed dogs for free motion quilting. I'm gong to try that when I finish cleaning it up. I'll give a better look underneath for a name. The only # I've found is the Z3351009...how would I look that up since it isn't a singer? I love this machine & have sewn on it for 5 years thinking she was a Singer 15-91

There may not be a name, though I have one that says 'Happy' on the underneath parts, and I have seen some with 'Brother'. Both are manufacturer names.
As for dating, you probably won't be able to narrow it down any further than it likely being from the 1950's or a little later. These were made in Japan after WW2.