This particular model of pillar was very popular in France during the 80s. It was sometimes used for certain models of alloy frames..the early elegant Altec (not Columbus Altec tubing!) ones coming to mind, and I have seen them used in frames such as Vitus Duralinox and TVT, and RBE carbon frames as well, although these frames did have standard means of clamping pillars.
One frame that relied upon the internally expanding pillar was the twin-seat-tubed Mecacycle Turbo, which was not built with any means of clamping the pillar.
I have sold quite a lot of these pillars over the years but never associated them with the ATAX brand, as they usually had Stronglight or Vitus stickers on them. If anyone ever needs a large supply of these pillars I know, where ther are several hundred of them!
ATAX, Vitus TVT and Altec were all based in or around Lyon and St Etienne..and the three framemakers sometimes used some of the same frame components..or at least the same manufacturer, a small engineering company also based near Lyon in the suburb of Grigny. The French cycle industry always wanted to use French sub-contracted labour wherever possible, and to have it as near as possible..an earlier version of the current "just-in-time" type of supply.
The castings for all the seat pillars and for the lugs of the RBE, TVT and Altec frames were also made in Grigny by Fonderie St Georges, just along the street from the engineers Duracycle (formerly Lyon-Raccords), who did all the fine turning and reaming, and just around the corner from the company that did the final polishing...making the products well and truly French. Vitus used the casting facilities of CLB to manufacture their lugs.
I recall that the ATAX/Stronglight/Vitus pillars were made in a variety of diameters to fit Reynolds (27.2mm), Vitus tubes (26.6mm) and the alloy frames at 25.0mm..
As the velo-orange website doesn't give any details of the diameters available from their stock, I would be grateful if Chris could post the info on the List.
Norris Lockley.."It's Raining Again"..Settle Uk