Thanks for the responses. I at first thought "Titan" as well, but don't recall ever seeing a lugged Titan stem. I also saw no "GB" or "S" markings which might have suggested a Schwinn-approved GB stem. That's also a massively long spearpoint on the lug. Again, something I've not seen before, though recognize that bulgie's examples showed pretty long spears. You can see a bit of braze metal blob at both the tip of the spear and the hollow of the curve near the stem bolt. I have to believe if it was a custom stem the builder would have cleaned up the shorelines better. So, perhaps some GB model as Mark suggested, but if so, why no "GB" (or "S") logo?