The secret to mounting the ball on both robots has come from scrounging through our plastics recycle bin to find a plastic jar lid or container for a thin, but stiff, flat area the size of the top of the existing metal ball castor assembly.
In the process I discovered that Finmark had a slight tilt upward at the front. The new assembly is a bit taller than the metal caster, so the old standoffs wouldn’t work. I really lucked out that some standoffs I were just the right length (when stacked), and even cured the slight tilt.
I was going to test it out this evening to see how much quieter it is, but now Finmark won’t consistently join the wifi network. This is the new Raspberry Pi ( as discussed previously). These intermittent hardware issues are getting really tiresome…
PS - happy to share the design file to anyone who’d like it
It’s worse with ROS, since the robot depends on the remote connection with my laptop for navigation. Would be nice to have the whole navigation stack running locally. But that would take more horsepower than the Raspberry Pi can provide.