METAL STEM & Threaded bowl
Could be a one off.. Courtesy of Ora Fleischer who has provided these images and details.
The pipe is stamped FALCON, so therefore must have been USA made. Ora says there is no stamping on the humidome as is the case with the Shillelagh. In the dimple under the humidome it is stamped PP4 indicating a standard length stem originally.
The finished length of the aluminium stem is 3 13/16 inch ( 98 m/m) indicating that, as might be expected, the full twist has shortened the pipe , but not quite down to Bantam size, although it looks as it the Bantam tube has been used.
The lower image shows the Shillelagh at top, the Helix (that is Ora's name for his pipe)lower
Larry Rathburn tells me that it was not unknown for workers at Falcon in Fort Wayne in the early days to experiment in their own time with pipes, so maybe this is one that origiated in this way.