Johan G:
Make your own circular slide rule
Johan G:
The most important difference
Johan G:
Back side of the third disc
Johan G:
Front side of the third disc
Johan G:
The second and the third disc
Johan G:
Photographing the second disc
Johan G:
Second disc, with grommet
Johan G:
Second disc, before grommet
Johan G:
Set up when photographing the disc
Johan G:
Under the hood
Johan G:
Improvised circular slide rule