At 3:40 PM -0700 7/4/01, Mark Bulgier wrote:
>Many lugged frames were made in brazing machines that wave an array of
>propane-oxygen "rosebud" torches pointed at the joint until an infrared
>sensor detects brazing temperature, then a wirefeed mechanism applies the
>brass. Brass can also be preplaced inside the joint as rings, strips, or
>pellets.
>
>Not sure when these machines were first employed, but I think many if not
>most cheaper lugged frames were made with these starting in maybe '85? I
>know the Taiwanese and Chinese have these machines but I think I remember a
>"Bike Machinery" (Italian) version too.
The old Raleigh factory in Nottingham did "furnace brazing" where the
frames, with pre-placed brass, were run through a furnace. Didn't
need no steenking robots.
>Ross had an interesting automated brazing method: tacked frames with
>preplaced brass were dipped into a molten salt bath that brought the entire
>frame up to brazing temperature, while also acting as the flux. I assume
>they modulated the cooling temperature to arrive at a heat treat state
>somewhere around "normalized".
I have a Mead Ranger built in 1916, and have a photocopy of a contemporary catalogue that says they were "crucible brazed." The frame is internally lugged, and, as I understand it, the different joint areas of the frame were dipped into a crucible filled with molten brass.
Sheldon "It's A Very Nice-Riding Bike, They Had It Figured Out 'Way
Back Then" Brown
Newtonville, Massachusetts
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