I've now spent an afternoon applying liberal amounts of a basic lithium grease (the grey type, not white) with a small paintbrush to any and all parts which may suffer corrosion, carefully wiping off the excess with a lint free cloth. All three axes run smooth and frictionless, easily turned by hand from end to end without any binding or unevenness. I think it's all good, but some sort of dust protection on the Z-axis would be nice. Any suggestions?

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