Shows how fragile the armtures can be.
Exactly! I've got a box of them too Julian.
Why did they make them like that RD . . .?? Well, I dunno! Everyone did similar, although I've only seen broken ones from Lucas, and K2Fs mostly.
Hard to compare the exact construction between makes without deliberately pulling good ones to bits, which isn't a good plan! The stainless R versions bucked the trend - very tasty. They made those in 15mm too, early on, and they are very solid. Last one of those I saw was on an early KVFR, late '40s iirc..
That said, BTH never upped their shaft diameter, 15mm on all their bike mags with rotating coils, and I've never seen a snapped one. Nor a Bosch, also at 15, with steel-in-brass. If BTH flange-mounts were an easier fit on a wider range of machines, then I think we'd see more of them out there. The KC2 as fitted to many 5 and 6T Trihards is a darn good thing, as is the KC1.
A while ago I was hoping to have a batch of stainless armatures CNC machined up, but only got as far as 2 prototype MO1 magdynamo ones. Designed them so that the through screws (capheads, counterbored) had their heads at the accessible end, not under the slipring, so in theory dead easy to get to bits. But like many things, a project that fell by the wayside. Design needed some tweaking to get a bit more thread depth at the 'wrong' end (which required some small tweaks to the coil design in its turn), and the usual things, life etc, got in the way. Here'sa pic of what could have been!
