Oh, you guys are great! I'm loving all this data - especially the Spring Motors up to the introduction of the Triumphs. I think that point is where numbering may have changed - we'll see (I hope). And the information on Triumphs (including patent dates) will be a big help to check accuracy.
Bob, I second Steve's request for a photo of that mandrel. I've seen rubber mandrels on some Edison coin-ops; do you think it's possibly one of those?
I didn't foresee our age being an impediment to this research!

Should have done this years ago, I guess...
Thanks again to everyone who has responded so far. Send the chiropractor bills to me!
George P.