@bar, I noticed that the new arms are a bit tight with the spools. At first, I assumed it was because of the 4.0 bolt issue causing grooves on the inside of the spools, but after testing with a spare unused spool, it seems to be in general. At least with with an original 4.0 model parts. In this video, you can see me spin the spare spindle on 4.0 arm and then on the 4.1. On the 4.1 arms, the spool is so tight it can hold on to the arm when picked up. I tested sanding (120, 180, 240 grit then hit with steel wool) the inside ring of one of my existing spools, and that does help. I would think that in addition to sanding them all, a small amount of grease would help that interface.
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Yeah I found this too.
I didnt sand or wire wool them.
It took several assembly and disassembly cycles to get them running smoothly at 900mA.
They seem to wear in pretty quick.
I wouldnt grease them because I think dust will just gunk it up in no time.
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I’ve also noticed that. The molds were made from the same CAD model, but they do feel ever so slightly tighter. It’s not necessary for them to spin totally freely to work well and I haven’t found the need to sand any yet, they should work fine as is, the tolerances are just a bit tighter on the new ones.