Mystery frame ID?
 

I've asked other places before but not here. Anyone have a clue who made this? Note the nicely sculpted head lugs. Fork crown is a Davidson/Takahashi MER investment cast, but that's about the only detail I can identify. Paint by Joe Bell, but he doesn't have a record of what it was either. Some very nice one-off hobby bike, or a top quality builder, and someone didn't want the builder's name on it? One other thing, It has no water bottle bosses, but it used to. You can see the remnants of them inside the seat tube. Somewhat unique shot-in stays showing the shorelines of the stays instead of blending them in. I got it from California so maybe built down there.
Bob Freeman
Mystery American made frame from late 80s | Flickr
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FWIW, it looks like an Ishiwata steer tube. Several builders used that seat stay attachment style.

Here is a picture of the whole bike.

https://cimg9.ibsrv.net/gimg/bikefor...797aefb29.jpeg

The fork crown reminds me of Dave Tesch, but I haven’t seen any of his with fastback seat stays. Dunno, but it’s very nice!

Yes, Tesch got his Takahashi MER crowns from Davidson. Later there were exact copies made in Taiwan, also some very similar knockoffs such as Ritchey, but Tesch only used Japanese-made originals. If you could hold them both in your hand (I have), the quality difference would be apparent.

JohnDThompson , do I remember right, Ishiwata splines are straight not helical? If so, Bob should be able to tell easily by looking, while this camera angle doesn't give us enough to go on.
Since Bob knows his Tange steerers very well, I'm going to put my money on Tange. He's not easily fooled.

I have a couple versions of that crown; one has pockets for pre-loading brazing material, the other doesn't. I think the one on the right is the original, Japanese Takahashi crown, the other the Taiwan knock-off:
https://cimg3.ibsrv.net/gimg/bikefor...b9b0375c87.jpg

Yes, Ishiwata has straight ribs, Columbus and Tange have helical ribs, but winding in opposite directions.
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That fastback style reminds me of Tim Isaac's frames, who was a big influence on Tesch, except Isaac's binder bolt was a blind hole.
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Welcome to the "I don't know who built it but it looks like a nice frame" club!!!
Lots of people have looked at Hilda and all say she has good bones but nobody can pin down a builder. At least yours has a nice paint job on it. Great shifter too!

I got her at the Trexlertown swap just after returnig from So West Asia in 2012 and we've been fast friends ever since.
https://cimg7.ibsrv.net/gimg/bikefor...5b9f8aa3f0.jpg

Getting a little attention in the spring of 2023. My sister made the graphics for me and the best thing about her is she's the only bike I can put a Portacatena on.
https://cimg8.ibsrv.net/gimg/bikefor...4028ebe6ae.jpg

The only small contribution I can make is that the blind allen key seat stay attachment was popular with builders in the Bay area of California and north. I vaguely remember visiting a builder (whose name I have forgotten) that did his seat stay attachments that way when I made a trip west in 1976. Tim Issacs was in Denver at that time because I visited him there on that same trip.

I'm surprised that if an investment cast fork crown was used, they didn't also use an IC bottom bracket shell too. I'm guessing that the lugs are the Prugnat model that had a kind of wing or tab that came out further onto the head tube. The builder reshipped and refined it to what it is now. Bulgie might still have that set of lugs in his stash.

A picture of the seat stay bridge might be an additional clue. Different models were sold at different times. Of course a builder can use one long after he bought it.

I am the least expert person, but it reminds me of a Chris Pauley frameset I saw online a few years ago? He did different things with the seat stay cluster if I recall.

I am sure you guys already cycled through that idea though.

That seat binder arrangement was also popular with CBS up here in Canada, a hallmark of builder Koichi Seki.