Yes... it was CD who posted the photo! My writing about the Free became so convoluted I shortened/edited it, and it came out all wrong.
It seems odd that Free would invent a new rename for their mechanism; they should have known it would confuse people long afterwards! The treadle I have is also remarkably smooth and runs freely.
Thank you, Cathy, for the info. on what became of the standard/osann/hexagon parts. Helen, indeed the needle bar housings tend to be unique. You are brave to disassemble them....and get them back together again. I've not had to do that, luckily.
Dianne in Colorado