If this bracket was built before 1909 then it would be highly unlikely to have been cast in aluminum bronze. Check out this pdf when you have a moment. biblical-data.org/MY_aluminum_Bronze.pdfI'm having more than a hard time understanding why timing would be critical. Aluminum bronze isn't new, and it isn't user friendly. It isn't generally used unless required, much the same as manganese bronze, which makes aluminum bronze look like a walk in the park.
Here is a cut and paste from the encyclopedia britannica
Awhile back a friend of mine dropped me off some brass scrap for my casting work. Most of it was just your typical red and yellow brass, but one piece quickly caught my eye. It had been broken in two by some sort of machine and the break was of an extremenly high shine as if it was polished.Aluminum bronze, any of a group of strong, corrosion-resistant alloys of copper containing from 4 to 15 percent aluminum and small amounts of other metals, used to make many machine parts and tools. Because of their golden colour and high tarnish resistance, the alloys are also used for jewelry and in architecture. Their resistance to oxidation at high temperatures and to corrosion, particularly by dilute acids, makes them useful for pickling equipment and other service involving exposure to dilute sulfuric, hydrochloric, and hydrofluoric acids. They have strength comparable to that of mild steel and are used for such machinery as papermaking machines, brush holders and clamps for welding machines in the electrical industry, heavy-duty gear wheels, worm wheels, metal-forming dies, machine guides, nonsparking tools, and nonmagnetic chains and anchors. Aluminum bronzes can be welded by the metallic arc process and can be brazed (soldered with certain alloys) with special fluxes.
So whats is this I though to myself. I tried some scientific testing of this beautiful looking stuff to try to get a better idea of what I had (if you consider hitting it with a ball peen hammer scientific) What ever this alloy is, it is impressive. Withstands multiple hammer blows barely leaving a mark, and does not file easily. I suspected it could be aluminum bronze so I started researching it a bit and became intrigued by its potential.
From my research and mindset I thought the bracket to be brazed in this thread would be a perfect fit for an aluminum bronze casting, although silicon bronze or yellow brass would be much easier to produce...