Step 1: Step 1: Create Your Design
Step 2: Step 2: Outlining
Make sure your Fill and Stroke Dialog is out (Shift+Ctrl+F).
Set your Stroke Width to 0.4mm , under the Stroke Style tab .
Convert your paths to strokes [Path>Stroke to Path (Ctrl+Alt+C)].
You should now have 2 paths, but to see that, set Fill to None , Stroke Paint to flat colour (Blue and Alpha to 255 if those got unset), and under Stroke Style set Stroke Width to 0.01mm .
Your outer path is the path to use for an inset object and the inner path is the path to use for a frame object . Use the Edit path by nodes tool to remove the undesired path segments.
My final commas use the larger outline combined with the smaller inner circle. The dots use the larger outline and the circular frame uses the smaller inner circle and larger outer circle to achieve the desired cut sizes.
It might be possible to accomplish the same task with Inset/Outset , but in the File>Inkscape Preferences>Steps>Inset/Outset by dialog, the units seem to be hardcoded to px and we're working with mm here so...
Step 3: Results: Unmodified
Step 4: Results: Modified
As with anything, prototype and do a test run of your designs before going into production.