Ken,
The Porta Cantena (PC) droupouts were all the short 1010/B type, not the long 1010 type (or 1010/A if no fender eyelets). Some older 1010's had a single, small, unthreaded hole right above the 10mm derailleur hanger eye. This hole was for the upper spring tab on one of the older Campy rear derailleurs from the 50's or 60's. I think the model was the Sportsman (it's in the archives). In any case, it sounds like that is the dropout you have. The PC dropout has two threaded holes (3mm x 0.05mm) and is always a 1010/B type.
The dropout that you have was made up to whatever date (I recall previous CR discussion, so, again, you may want to check the archives) , but they stayed in use by some builders for a long time after that. Even moreso than components, frame parts only serve to provide a maximum age for a frame. That is, a frame can't be older than the earliest date for it's dropouts, or lugs, or tubeset, etc. On the other hand the frame parts might have sat in a shop for many years after the part was no longer being manufactured before being used on a frame.
As for the earliest date on the PC, I'd take 1978 with a grain of salt. It showed up in the 1978 catalog 17A supplement that also showed the type 2 SR rear der, the SR one-bolt post. While I'm pretty sure the revised SR parts were actually introduced around that time, the catalog also marks the first appearance of the 1010/B droupouts, which in-the-know CR framebuilder guys tell us were available several years earlier. (While the 1010/B does not appear in rthe 1975 Catalog 17A, I've heard it was available by that time.) Please note that the first catalog depiction of the 1010/B is actually of the PC version, so it's possibe that the basic 1010/B was available for some time, but that the PC version was new at the time. On the other hand, the fact that the 1010/B in general went uncataloged for a long period suggests that the same might be true of the PC version, the PC shifters or the hangers. Interstingly, the PC shifter shows up ONLY in the 1978 supplement, and is gone by the next catalog (1982), though the hangers continue to appear.
Another interesting point is that only the clamp-on version of the PC shifter is shown in the 17A supplement. The braze-on version was never depicted or listed anywhere, though I'm sure Campy made a braze-on version because I have one in a factory-sealed package.
The whole Porta Catena thing came and went pretty fast, and very few people had any use for it. Adding dish and/or losing a cog was not worth the minor convenience factor. The dropouts were made in huge numbers though, and were in use for many years. As Mr. Thompson said, Trek was using them in 1985. The only set I have are on my 1985 760.
In the end, the PC is one of many interesting but not-quite-right innovations from Campy.
Tom Dalton Bethlehem, PA USA
Subject: RE: [CR]Campy Porta Catena (sp?) dropout useful for dating frame?
Not to hijack the thread, but does anyone have a picture of the dropout drilling? My early '80s or so Mondonico has 1010 dropouts with one small (too small for fender bolts) hole in the drive side part. I've always wondered it this for a Porta Catena.
This thread constrains the date of my Mondo to not earlier than 1978, so thanks!
Ken Freeman Ann Arbor, MI USA
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