I thought I'd share a photo of some Ruckstell serial number plates from my collection, from the earliest until the end.
Here is one from our Canadian Ruckstell. Note the Manufactured by. Canadian Acme Screw & Gear Co. Ltd Toronto.
I found two Ruckstell patent plates in my collection that have serial numbers over 600,000. The highest number is 630,602, so he obviously made more than I originally thought.
I've seen two examples of Canadian Ruckstell plates that are oval shaped.