Kriegsmarine manufacturing methods

[John R]

Just a general topic about the techniques of manufacture for the KM badges. It is my understanding that two methods existed, the die-struck and die-cast. It seems to me with die-struck, that there would always be an edge going around the badge that would have to be finished by the manufacturer that would appear as a line when complete. So therefore, all tombak badges would have such a line.

With a cast method, I assume a wax or plaster mold was available, and the zinc or other metal poured into the mold and no line would exist.

For cast reproductions, perhaps a line would exist since the mold would have to be cut I think to get the original badge out of the mold, then the mold reattached somehow before the new hot metal was poured in.

Anyway, I do not know and am looking for better clarification on what I am seeing on both the orginal tombak and zink badges and also the reproduction cast versions.

[Gordon Williamson]

Die struck badges are generally stamped from a strip of sheet metal, using two tools. e.g. a U-Boat Badge, first a blanking die tool stamps out the basic part which will still have a "flashing" of metal around the edges and has a "solid" centre. This is then put into a finishing tool which crops off the excess metal around the edge and voids out the centre. This second operation is what gives the shear lines or striations around the edges.

Cast badges using similar die tools (not moulds) but instead of being stamped, molten metal is forced into the die under pressure. This allows parts like the hinge, retaining hook etc to be formed integrally with the badge. Again there will be a "flashing" of surplus metal around the edges and in the centre which is cropped off using a finishing tool.

In both cases, die stamped or die cast, there will be striations around the edge, but not a casting line like you see on cast fakes, which are low volume production pieces in which the metal is poured into a mould.

This planchette for a U-Boat clasp will show you what I mean re the flashing of excess metal which has to be cropped off.

[John R]

Thanks Gordon,

For some reason I thought the badges were made somewhat like a coin would be made thereby leaving the line. I was arguing with a machinist over the subject and it turns out neither of us knew what we were talking about. Your photo and explanatiion clears it up.

John