Spindle noise for a few seconds during warmup

[awalt1250]

I have the desktop with the 1HP HSD spindle. Lately during the warmup routine I am hearing a different noise when it first starts up. The noise only lasts for about 10 seconds then goes away. Is this a sign of things to come..i.e. bad bearings or a rebuild/replacement?

[ssflyer]

I have the 2.2 hp HSD, and it does the same thing. I don't have any measurable runout, and as you say, it stops after about 10 seconds. It's pretty much done it since day one, and that was several years ago...

[awalt1250]

Thanks Ron. I was getting worried.

[Bob Eustace]

Same as Ron - always been the same.

[dlcw]

The ceramic bearings need to heat up and expand to fit tightly around the spindle shaft. At least this is what I was told. Mine makes a sound like sanding a piece of wood with 80 grit paper. And it's fairly loud. After about 10-15 seconds the noise goes away and I can stand next to the spindle while warming up and can barely hear it.