Thanks for the note, Amir. I've <snipped> to focus on one matter:
Amir Avitzur wrote:
<snip>
> Schwinn Paramount hubs have unique screw-on flanges (or so I heard).
> Airlites, Duralites, Bayliss-Wileys, etc had press fit or thermal fit
> flanges. I'm curious if any other company used this design.
<snip>
Thanks, Amir, for getting me to look closely at the Paramount (rear) hub
and an Airlite Continental that I have. The details of construction are
quite different. On the Schwinn Paramount rear, the left rear flange is
a press-fit, but the right rear screws on, using the same thread set as
the cog, which butts up against it. So, the hub shell proper (in steel,
reputadly 4130) has shoulders on both sides against which the aluminum
flanges seat. This is actually allows pretty easy assembly: screw on the
right flange, and then check spoke hole alignment before pressing on the
left flange. Benefits? (1) the sprocket threads are steel, not the
aluminum of the flange. (2) the races could be turned and ground from
the same forging as the barrel, assuring concentricity, minimizing
assembly costs, etc, but at the cost of more machining of that barrel
assembly.
In contrast, the Air-lite rear differs. The flange looks like it was pressed over a smaller barrel. Certainly the sprocket thread assembly is part of a single aluminum piece that includes the flange. I don't have time to disassemble that this morning, but I happen to have an early Campag 3-piece from the FB factory. That has AirLite-type construction, and one can clearly see that the bearing race has been set into the flange-sprocket assembly.
So, I don't know if the Paramount design was unique, but it was different from those two. Thanks for sharpening my eye-balls!
harvey sachs
mcLean va.