I picked this up on craigslist for a song. It is beat up really badly, but should be ride worthy. I know nothing about its history but it seemed sketchy. The cheap white rattle can paint is obviously not original. Judging from the fork the frame was most likely a yellow color. It has a vintage Shimano 600 headset that I'm guessing was original to the bike, but who knows. Shimano Dura-Ace 7402 crankset, 600 EX brakes and levers, 600 front and rear EX (RD 6207) derailleurs and downtube shifters, Campy hubs. The parts seemed all over the place so who knows if anything was original. It has Campy forkends/dropouts on the bent and destroyed forks as well as the frame (luckily only pelted with dents and not completely useless). I've photographed some of the seemingly more distinguishing characteristics to help, but I'm totally baffled. I thought the fork crown was sort of unique, but maybe not. The bottom bracket English threads, 68mm. 126mm rear dropouts. Guessing it is Japanese. Frame weighed about 4.6 lbs (with seat post binder bolt) and is 60cm center to center. Serial numbers under BB shell 14101 and 21588. Eager to hear what members have to say. Thanks for looking.

hmmm...not too many Japanese frames with Campy DOs and forkends. The BB shell looks kind of middling and maybe has a welded seam, the fork crown looks a lot like a Tange crown(any stamps on the steerer?) the other details look pretty nice: lugwork and fillet brazing of the brake bridge, etc.: very tidy.
I couldn't rule out Japanese but the serial number sequence doesn't ring any bells
What size seatpost?

No marks or stamps on the steerer. The seatpost in the bike was a SR Laprade 27.0, but I wonder if it was just put in to fit because they didn't know any better and it was actually 27.2. Not sure, but seat tube diameter is 28.6.

When I inserted the seatpost past the min insert with the binder bolt completely loose it wiggled inside ever so slightly. If it was 27.2 hopefully didn't cause too much damage, but I think I do see a slight bulge in the seat tube.

According to frame builders... Haden fork crown and maybe, looks like, Prugnat lugs. Maybe custom build.

maybe a Haden, but the "Europa" has a bit different contour to the socket edges, plus it would be stamped "haden" above the hole. but maybe filed off or filled in. The Tange C-10 is clearly modelled after the Haden, and they show all their crowns undrilled, but obviously most were drilled for brake in production.
Very well could be Prugnat lugs, but that's another model lug that got copied by others (including Tange, howaboutthat?).
If you really get a good fit with 27.0 it's another clue that the seat tube might be Japanese, but you should try a 27.2 (and make sure the tube is prepped and round) before assuming 27.0 fits.
I'd be leaning toward a "custom build", too except for all those serial numbers in the BB, that's a lot of stamping for a low-output builder.

that's a keeper if its your size!

Yep... for sure. It isn't pretty in some ways but will make a really nice beater. Just have to find a decent, cheap replacement fork. It'll be nice to have a bike of good quality that I don't have to sweat something happening to. Just gonna prep it, slap some spray paint on it and enjoy it.

Thanks for helping me try to make sense of this. I agree the Tange and Haden crowns look very similar. Tange must know a good thing when they see it and besides you know what they say about imitation. Definitely going to try the 27.2 out. I heard from another source that it looked like a batch frame from the UK or Japan. Spring is here and I'm gonna have some fun building and riding it.

I'd be on board with a UK guess....although it really does fit with many of the mid-range Japanese/Taiwanese bikes I came across years ago when I was a framebuilder and then mechanic. The seatstay caps, lugs and fillet brazed brake bridge all edge toward a well made frame, but I wouldn't think it was a custom build. FWIW, KHS did build quite a few frames with Campy dropouts (as per the John Howard KHS I had years ago). But the fact that the vent holes haven't been filled and the quality of the BB shy me away from the custom idea as well. Do you have any shots of the inside of the headtube? Curious whether there are vent holes in there or not. If you put your finger up into the seattube/downtube at the BB, can you feel any "pins" sticking out? That would be a sign of a pinned frame which would mean it was hand brazed, but LOT'S of big builders use this method in mass production. At any rate, what everyone else said....looks like a nice frame to have some fun with!

Here are some more pictures. I did not feel any pins of any sort in or around the tubes when reaching into the bottom bracket shell. I can clearly see the seam in the bottom bracket shell. Am I right in assuming that this is a cheaper production method?

Post a pic of the whole fork. You might be able to have someone with a frame table cold set it if it's not too bad.

There is a sizable dent on one of the blades. It doesn't appear to be creased but that is where it looks like it throws the alignment off. I didn't receive a back story on how this happened and I really am not sure why it did. I believe I'm right in assuming that it would be bad if it bends where the steerer tube enters the crown and I'm not certain if it does. Regardless it would be great to cold set it back to a usable state if the price were right. It was a really nice one IMO and no other will fit this frame as well. Did the best I could with pic's but sort of hard to capture that dent correctly.

I'd take it to somebody and TRY to get it straightened before giving up, but there's multiple things amiss with that fork and it might be too hard to correct them all.
It's odd that whoever built it used a cheap(er) seamed BB shell but didn't scrimp on any of the other frame bits AFAI can see, and the construction looks clean and careful...indicating either a good production facility or skilled hand builder.
Aside from the above mentioned KHS frames that used Campy ends the only Asian production frames I can only think of are maybe Panasonic and possibly some of those "Ital-Japanese hybrid" one-offs from Nishiki and Centurion.
I don't think your serial numbers go with any of those brands, but...this is when T-Mar would really be a huge help!

Big discovery! While stripping the paint I found the down tube stamped Reynolds 531 Butted 20/23! That may help a bit, dunno... but helps me know what tubes I've got regardless.

and THAT's a big clue, pointing away from Japan and toward a 27.2 seatpost. Might be UK, but doesn't rule out some other locations including No. America.