I don't have anything exiting to report, but I am working on some future projects.   

I'm still working on my belt driven rotary axis.  To help with the design I picked up a 200 mm belt and two pullies, but I don't think I will use the larger pully.  I can get a better reduction ratio by printing my own pullies, and it will make for easier assembly in the end as well.  Anyway I'm still in the design phase, but right now I'm looking at a 50 mm and 16 mm pully set to get roughly a 3:1 stepdown ratio.  I'm just getting started on the design but hopefully it will go smoothly.

I saw a note the other day about how without a baffle a box fan will reverse the flow of air at the edges.  It piqued my interest and so I reached out and picked up a $6 anemometer from Amazon.com.  It is crazy what you can buy for next to nothing.  I can't remember what the original site was, but it was probably one of Matthias's videos or maybe this filter project.  Again I have not found time to really play with this yet, but I did verify that the edges of my box fan are in fact sucking air backwards through the filter.  Anyway it should make for a fun distraction, whenever I get the chance to experiment.  My plan is to profile the cross section of the fan and verify that adding a baffle it in fact increasing the flow across the full area of the filter.

Finally I saw a comment about spindle runout and so it is on my list to look into my spindle to see how much runout I have.  I looked into buying a test indicator to make this measurement easier, however the reviews on reasonably priced indicators are poor, so for now I will stick with my dial indicator and see how well that works.