After yesterday’s post, Dan Linn sent me some pictures of a Number 830 Eagle Torpedo from his collection:
His has the earlier knurled top:
Which is consistent with the earlier of the two patents from the "class of 1909," Claes Boman’s design patent issued on April 9, 1909:
"Pat. Appl’d For." Boman filed his application on January 13, 1909, which pinpoints this pencil to the first quarter of 1909.