HP 97 paper advance rollers

[Raymond Del Tondo]

Also note that there exist at least three different incarnations of the axis.
The first version, much like that used in the 97, has a decreasing diameter from the outer edge to the raised center rim.
The second version, maybe from 1981 to late 1982, has a steady diameter from the outer edge to the rim.
The latest known (to me) version has a rising diameter from the outer edge to the rim.

If you think that the early version might suit best, since it prevents the O-rings from sliding off, be aware that if you use kinda O-rings like for the card reader, the total diameter might not be wide enough.

The result will be a print head which shreds the paper at the edges, or at least which will leave scratches at the paper edges.

Better use axes of the second or third incarnations, or use suitable O-rings with slightly bigger outer diameter.