I have been buying and occasionally selling vintage parts for a long time and in over 20 years I don't believe I have had that many problems. I believe that you therefore need to refine your search and buying skills. Wherever possible always buy with the part physically in front of you. Where possible, buy from people who collect themselves and are not only sellers and ask them why they are selling the part. When not buying in person, always insist on clear photos and if there is any doubt ask for clarification or always expect things to be the worst possible case. When buying online or by phone always expect the worst, which does not mean that should not consider teh deal, but simply that you need to keep this in mind when determining the price. In fact many of my best deals have been sight unseen purchases where I paid a fraction of the price that I would have paid had I seen the parts.
American Friend":dga02fr3 said:
- A NOS Campag NR rear mech that turned out to have a lot of play in the upper pivot. A factory second?
Was the derailleur in the box? If not in the box, why not? This is always a red flag when you find a NOS part that is not in the box. I would rather buy a little used part than one NOS that is no longer in its original packaging. I am however somewhat puzzled by your description of "a lot of play". What you perceive as excess play could well be paint on the dropout or something similar. In fact it is far more likely to be related to the dropout than to the derailleur.
American Friend":dga02fr3 said:
- "Excellent" Campag NR front mech with bent stuck adjusting screws
These screws can readily be straightened and it is very rare that they are permanently stuck. I have friends who have had very good luck using ultrasound cleaners to unstuck these screws. Furthermore, bent screws can readily be seen in photos. As a buyer I always insist on photos of the parts. It is also in the best interest of the seller to provide photos, because there isn't much to prevent the unscrupulous buyers from claiming that a damaged art that they already owned was the part that they just purchased (this has happened to me as a seller; however with the photos, I was able to prove that the damaged part in question was not the one sold by myself).
American Friend":dga02fr3 said:
- "Excellent" Campag NR seatpost that was 0.4mm smaller than stamped diameter and a lot more scratched up than expecting
It is my experience that Campagnolo seatposts tend to be smaller than the indicated size, which also makes sense insofar as they must fit into the indicated size, so to find a 27,2 measuring 27,0 is not overly uncommon. 0,4 mm does seem to be on the extreme side. I would remeasure your post and see whether the diameter is the same throughout or if it has been ground down somewhere. As mentioned previously, with good photos or when buying in person the effective amount of scratches can be correctly judged.
American Friend":dga02fr3 said:
- "VGC" Campag NR brakeset that looked like it was thrown together fom spare parts and still missing the serrated washers, lever grub screw, and had 2 useless blocks in 2 very corroded shoes.
The serrated washers were not originally supplied with the brakes in the 60's. They were added in the 70's. So if an older set of brakes, their absence might be justified. When speaking of the grub screws, I take you are speaking of those that bite down on the brake lever pivot in such a manner that the pivot cannot slide out. While it is indeed far better to have these, their absence does not make the levers unserviceable or unusable. These are also not parts that I expect anybody to check for insofar as one does not normally ever touch them (in fact apart from the case of replacement of the lever blades, there is never a reason to touch them). For brake pads, I have recovered many a pad by simply filing away the oxidized outside layer of rubber, getting to the underlying rubber that has not been exposed to decades of atmospheric agents. In fact, nobody should ever expect any brake pad that is a few decades old to work properly as is. As far as the corroded shoes, Campagnolo chrome is very frequently such that with some very fine steel wool they are fully recoverable. Again, with proper photos or in person purchasing, the lack of serrated washer and corroded brake shoes would readily be visible.
American Friend":dga02fr3 said:
- "VGC" Campag Record front hub with a loose cup
This would be a first for me. I take that you are describing the press-fit race inside the hub. What makes you think it is a loose cup?
American Friend":dga02fr3 said:
- "Good" 3TTT stem that had been cut down by around an inch and was very scratched up not just on the quill but also on the top of the stem
Most sellers that I know who rate a stem as good mean serviceable at best, which seems to be the case here. Again buying in person or with proper photos would have avoided this situation.
Lastly, remember that there is generally a good reason why a part is still available in NOS condition a few decades after it no longer is produced. It could be because it was totally superseded by newer and better parts (i.e. tubular rims of the late 80's and 90's, pedals for toe clips in the late 80's), or were oddball parts that nobody ever really wanted (i.e. 24 hole hubs); don't ever be in a rush to buy parts and always ask your friends first, they will always be your best sources.