Following up on some tandem headset details, I have two tandem forks,
one for 650B (red painted) and one for 27" (chrome), both French
threaded (28x1). The steerer tube dimensions are 28.05 OD, 22.0 ID.
Interesting thing is that they are hand labeled, one marked "French
thread 28x100", and one marked "1-1/8" with no thread info. Not sure
who built these, but they use a twin plate-type crown, the lower plate
having fender mounting tabs protruding front and back of the lower
plate. The red 650B fork has Campag drop-outs with single eyelets.
The chrome 27" fork has unmarked Campag-looking forged drop-outs with
double eyelets. Other than that, they appear to be produced by the
same maker. I can take some pix if there is interest.
--
Wayne Bingham
Lovettsville, Virginia USA