Hey SB'ers,

I have recently noticed an oscillating hum in my spindle (HSD, Model: AT/MT1073-140). Obviously no noticeable during machine (noise), but if the cars are sitting idle, there is a Hum which comes and goes while the Spindle is running. Currently running at 15k RPM. It almost seems like an imbalance or perhaps bearing?

Thanks,

Brandan Smith