"William H Maple entered ABNC on January 22, 1906. He engraved stamps and ornamental figures on bills for several countries and his last works went to Canada in 1939."
Above info taken from article entitled LOS GRABADORES DE SELLOS Y BILLETES CHILENOS DE LA AMERICAN BANK NOTE COMPANY by Jorge Torelli M.
Download it from http://www.mascoleccionismo.com/pub.../AFE-017.pdf
Hope this helps, albeit six years late! GLENN