Originally Posted by MrsBoats

I have a Riccar 310b, and when I got it several years ago, I tried to date it. Riccar still exists as a company (http://www.riccar.com/), but they only make vacuums these days. I emailed them anyway, sent them a serial number and a picture and asked what they could tell me.

Turns out, a fair amount. Their records aren't as comprehensive as Singer's, but they dated mine to 1964 and were pleased to hear she was still chugging along. They even sent me a link to the owner's manual.

One of their customer service reps is the sewing machine person, so it may take a couple days to get back to you, but I found them very helpful.