The voind robot design is based on a swivel arm that rotates on a horizontal shaft driven by a worm/wheel combination gear. This shaft has a very simple design with a 10mm main section and a 20 mm narrower section with 6mm diameter.

To fabricate the narrower section we decided to build a small combined Milling/Lathe machine from MDF board. This contraption basically holds firmly a small rotating tool with a small drill and at the same time allows a 10mm shaft to be fed and rotated against the mill.

After a quick test we were good to go at machining the end of our aluminum shaft. Check the actual footage below:

After the operation the machined surface shows a scaled aspect due to the manual feeding of the shaft.

But after a quick sanding with fine sand paper the result looks very smooth:

You can see below the wheel firmly clamped to the new shaft and being driven by the worm.

Update:

This aluminum shaft proved to be too much flexible. A steel shaft will have to be used instead.