Wayne,
Hopefully you received my pictures from earlier this morning (...or at least it was early in my corner of the world).
Regarding vintage Campy outer chain rings, they changed from 151 BCD to 144 BCD in 1968, first introduced the chain "roll-off" pin in 1974, and went from being marked "PATENT CAMPAGNOLO" on the inner reinforcement ring to "BREV CAMPAGNOLO" on the outer portion near the teeth in 1978.
As for the finish peeling that you mention, these rings would normally consist of aluminum alloy with a protective clear anodized coating - they are NOT chrome plated in any fashion (...yes, there are exceptions such as when someone intentionally removes the anodized top coat, then drills and re-profiles portions of the ring, and elects to simply polish it to high luster thereafter sans anodization - viva Mexico). Typically, these chain rings will not show the effects of oxidization or having the finish "lift" unless their anodization has been somehow compromised, such as from chafing against the tooth washers originally fitted on their back side at the chain ring bolt holes. Of course, if you drop a chain, or otherwise scar the inner or outer surface of the ring wherein the anodized top coat is removed from a portion of the surface area, you then invite the prospect of further damage or erosion to said finish as the result of it being unnaturally and unevenly exposed to the elements.
Regards,
Robert "...temporarily chained to a desk" Broderick ..the "Frozen Flatlands" of South Dakota
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Wayne Davidson Sent: Friday, May 26, 2006 4:12 PM To: CR List Subject: [CR]Campagnolo NR chainring info required
Hi all, I have a Campagnolo NR 54T outer chainring, pat without peg, the chrome plating seems to be started to lift in places, or maybe saying that the alloy is bubbling underneath might be better. I checked the archives and found no talk on such matters, any clues as to age? TIA wayne davidson Invers NZ.........