After WW I have start cooperations and / or shares were changed between silver flatware or hollowware producers and supplier of their basic material.
In case of Franz Bahner it's visible in change of maker's marks: «Lions head» until 1918/1919. From 1919 on «F crossed hammer B» and from about 1925 on «M (top letter) crossed hammer S (base letter)». Crossed hammer significates shareholder «Mansfeld Silver Mine PLC» - first in cooperation with Franz Bahner; later: main shareholder.