I do like the idea of a plus or minus 90% �rule� for most of the frogs which are encountered.
Before this thread I had frogs sorted by type ie: Luftwaffe, Police, Navy etc. The thread has made me rethink that approach and I now use a date sort and am refining it a little to deal with the undated examples. As commented on, there are a number of exceptions which I think makes it even more interesting when setting the parameters. For example: In a quick resort I found two aluminum riveted 1935�s. A 1940 (or later) Police frog using copper rivets with brass washers. A pair of steel riveted black Luftwaffe frogs by the same maker in 1940 (one all steel and the other with aluminum washers). A 1940 dated frog with aluminum washers and copper rivets. And a 1941 dated frog with both aluminum and copper/brass rivets and washers. With all of the different makers involved it seems obvious that some had larger stocks of previously manufactured components than others. And that as they ran out of old stock began to use steel. I also tend to like the �strategic materials� argument a little more because when the frog studs (for tie straps) are looked at by 1942 the aluminum studs seem to have virtually disappeared.
Posted below is another exception: The �no rivet� frog (no holes, no evidence of rivets/washers) which came with my 1941 crs �Tr� marked bayonet, Which when I found it looked like it had been on it forever. FP
