...I suspect that's a difficult geometry for FDM in PLA.

These sewing machine shaft collars are kind of tricky: thread unspools around them, so the inward face must have a completely smooth edge that can't catch or snag. This rules out a simple clamping-style shaft collar with a slit in it.

Spool Cap (Small)

ADPClientService is a (currently) non-essential background service that collects juicy user data to send to Autodesk, since there's no way they could be expected to make ends meet on just $545/year licenses alone. You can find lots of threads about how to disable it in various Autodesk products, but none of these instructions appear to work in the current version of Fusion 360.

It stopped doing it as soon as I started watching it. But just wait, I'll catch it in the act. >_> <_<

An easy optimization here is likely to avoid calling phutil_utf8v(...) on very long strings using a strategy like this:

• Slightly smaller diff.

They sell "broken" Ender 3 printers on eBay for like $75 shipped. I ordered two. One had a bad board (a $40 part); one had a bad Y limit switch (a $3 part) -- so the actual cost per printer seems to be around ~$100 if you're familiar with how they work and can identify which parts aren't working.