Thanks to everyone for their contact regarding my Quest for an elusive chainring. I believe I should clarify just what these rings were with some further information:
TA made several chainrings which were all drilled with a 5-hole inner circle, intended to attach directly to their TA "Professionel 5-vis" cranks, as well as to the Stronglight 49D and many others which all shared the common 49 mm (2 inch) BCD - which had already been in use for many decades.
The TA 5-vis "outer" rings all looked very similar; they had 6 arms and all originated from the same forging. They were then bored with 6 additional holes to attach two or more "inner" chainrings directly to those primary outer rings. TA made a few different drilling patterns:
1. "Cyclotourist" BCD 80 mm.= smallest inner chainring: 26 teeth
2. "Criterium" BCD 152 mm. = smallest inner chainring: 43 teeth
3. "Randonneur" BCD 116 mm. = smallest inner chainring: 36 teeth
The last model is rarely seen. It was probably no coincidence that the 116 mm BCD is the same diameter found on old Stronglight, Magistroni, and many other Steel, cottered cranksets all of which shared a common 3-arm pattern.
I would guess that the production of 116 mm rings for the 6-arm, 5-pin cranksets seemed to make perfect sense to TA... at least initially.
This was also the same BCD eventually adopted by TA for their "Professional 3-pin" crankset.
However, perhaps TA soon decided that the small "cyclo-" chainrings really made this size an unnecessary duplication - one which they would also need to stockpile - and just for the sake of a few mid-size inner rings.
So, for what ever reason, TA seems to have either quickly dropped the model entirely, or simply never distributed them widely - at least not in North America.
This is unfortunate, because I think they were a very useful size. And, placing the chainring bolt closer to the teeth of the inner ring probably made that chainset more rigid than the 80mm BCD fitting.
You may notice that in recent years FSA and other manufacturers have introduced "compact" road cranksets with a 110 BCD these all accept small inner rings of 34t... very similar to the old TA Randonneur crankset.
So, if anyone does indeed come across any 36 tooth 116mm BCD TA alloy chainrings, by all means, please do let me know... Or, certainly, just save them and treat them like little treasures.
Bob Hanson, Albuquerque, New Mexico, USA