Ian,
As info, G.B. Crandall passed away on January 7, 1953. I have a reprint of a very extensive article on Tobin, Woodstock and G.B. Crandall. It was given to me, at my tables at the Woodstock gun show, by the author, Alvin Pearce Hunter, of Mt. Elgin. He knew Crandall well and visited with him in his shop in Woodstock on a number of occasions.
Crandall was a fairly prolific inventor as well, having patented a powder measure, horizontal loading press, bullet swager, ported choke tubes, and his own gun oil which he called No-Ko-Rod. Remind me to show you the book when you're here.
Best,
Ron.