Hi Guys, In order to provide a more clear answer to Kilian's question, I will throw out my general rule as to the compostion of leather Wehrmacht S84/98 III frog rivets through the years 1934-45. 1934-1935:Copper with 1936 being a transitional year with most being aluminum in 1936. 1937-1941:Aluminum with 1942 being a transitional year with both Aluminum and Steel about equal in 1942. 1943-45:Steel There are exceptions to all rules but I will submit that my rule will stand at least 90% of the time. It appears that failures of the aluminum washers under extreme use and Aluminum's value as a strategic metal ended most it's use after 1942 as a leather joining material. Here is my near mint 1942 frog with both aluminum and steel washers used with aluminum studs. Hope this helps! Jeff Bernsh---Owner Tenmile Creek Antiques Ltd.
