While fettling the blue'un with its hotchpotch of parts I remembered that the front mech, a Shimano 600 came off my Falcon Majorca bought as a teenager with my Saturday milkround money, so its now 35 years old. However, a quick glance at the tandem put that in the shade: original Dura Ace hubs, a Simplex push-rod front mech and out the back a black Shimano Crane GS, all of which were suggest a new date of about 1973. The tandem was second hand when my parents bought it in the early 80's. All those parts are working just fine, 41 years later.
So it got me thinking: what's the oldest kit out there still in regular use? (Perhaps we should exclude frames from this as some seem to go on for ever.)