Gene, I'm glad you brought up the topic. After this thread first appeared I've been looking over my own Campy brakesets. I discovered the same "SL" stamping on the back of one of my brake caliper arms. This is on one (yes, just one) of what I would assume is indeed a pair - all the specific tiny parts and the finish quality match perfectly.
In this case it is on the back of a "Small Front Brake Stirrip" (cat.#2040/1) which was part of a shorter reach (47mm.) caliper set, with "patent" on the center bolt, block lettering, and "bump" on the Q/R levers - so I'd assume they're from later half of the 1970s.
Apart from that marking there seems nothing remarkable about these particular calipers, and nothing to distinguish the front from its un-marked rear mate (except of course the typical front rubber 'bumper'). So, I doubt your stamping was added with the bike-specific pantographs.
Got me curious now, too! Appreciate any further info.
Bob Hanson, Albuquerque, New Mexico
Eugene Powell wrote:
...I've been cleaning and detailing a set of "Gianni Motta" pantographed Campy brakes and noticed something. The backside of these arms are as well polished as the fronts, as nicely finished as any area of any Campy part I've ever seen, and stamped "SL". Upon inspecting several other Campy brakesets I found the odd flaw, cast mark and generally a finish one might expect on the backside of something where the backside isn't likely to suffer close inspection.
Did Campy make a "SL" brakeset I've never heard of?
Was this mark and the extra attention added by the pantographers?
Anybody have any thoughts on this?
Gene Powell
Rad Finishes
Portland, OR