Spindle funny noise

[routercnc]

Couple of long shots.

Might be one of the bearings in the spindle is not seated properly and is skipping around. Loctite might sort it but does mean spindle disassembly.

Or electrical connection to spindle is arcing - does this have a plug on the top of the spindle. Take it off and check for arcing / black on the pins. Check the wires are tight into the VFD.

[foto-boss]

[magicniner]

If I leave it several months without use my little CNC mill spindle motor will make a similar noise until it warms up if I run it above 5Krpm, it seems to be electro-mechanical noise generated when the motor slips a little too much and the VFD tries to sort it out.