Originally Posted by
hoyc
I'm thinking Japanese as well due to the Shimano dropouts. Was it common to see columbus tubing on Japanese frames? That is the only thing that seemed out of place for me.
Not necessarily. Trek used a lot of Shimano SF dropouts on frames built with Ishiwata, Reynolds, and Columbus tubing. IIRC, there were some supply problems with Campy 1010 dropouts for a while in the early 80s. I've seen Shimano SF dropouts on more than a few British frames as well, perhaps for the same reason.
The fork crown on your frame does remind me of Japanese production, though. Is there anything stamped on the steer tube? Any rifling inside the base of the steer tube where it is inserted into the crown?