@mactec54:
Hi ... & thank you also for your feedback
As to your question about the settings of my VFD I actually think that I am using the settings you have suggested here:
https://www.cnczone.com/forums/spind...ml#post2071668
I have changed a couple of settings like e.g. the start up and stop intervals so that it ramps up speed and stops relatively slowly. Also, my spindle is not an air cooled version but water cooled.
I have used it on some occasions to mill e.g. cast iron (relatively slow speeds, low depth of cuts, "carefully"), and normally it goes fine - but, well, this time "something" that I don't exactly know what may be happened and caused these odd sounds. However, yesterday I decided to run it free wheeling for some hours - slowly increasing the rpm up to max - and it appears to be back to normal (real milling obviously is needed to reveal if this is actually also the case) ... So, for now, I don't exactly know what happened but I have made a decision to be more careful with the drive/spindle onwards. Fortunately normally I only mill non-ferrous metals, plastics and wood so hopefully it will be fine ...
Cheers,
Jesper