Here is a process for converting regular fonts into single line strokes.
1. Compose Your Text
Select your text and an appropriate font for the cutters you wish to use.
Here is a good example of a font that is basically the same thickness throughout.
If we were to encode this character as an 'inside' cut, a 6 mm cutter (as demonstrated by the red circle below) may not be able to cut the entire character out. So we will convert this character from outlines into a single stroke for cutting as an online path.
2. Convert Text to Outlines
Select Type> Create Outlines
3: Offset the Paths
Select the paths and perform an offset: Object>Path>Offset Path
With preview enabled, experiment with negative values in the Offset field ( start with small values , as large values will collapse on themselves and fail to generate offset geometry) until you get a continuous path that is as close to the center as possible. Then hit "Ok" to create a new offset path.
4: Change Colors, Lock Layers and Trace
Change the color so that it is visible. (Here, we have added a blue fill)
In the Layer Window, lock the layers you just made so that you don't select and move them by mistake while tracing.
Using the pen tool, select a new stroke color (green with no fill in this example) and trace the center line.
5: Make the stroke match the cutter
Edit the stroke weight by hitting the stroke button with the path selected. Make it the cutter diameter you wish to use (you may need to change your stroke weight units in preferences from points to inches)
Note that the cap and corner settings have been changed to reflect the behavior of a rotating cutter.
6: Color Code for Origin
Now, simply change the stroke color to grey and delete the original font and offset elements.
You now have a single line letter to cut.