Chinese 2.2kW spindle - wow & flutter

[Jonathan]

Depending on how you're measuring things, the difference between the electrical frequency and the spindle speed (called slip) could come into play, especially at low speeds. But if the discrepancy is there at no load, it's not that.

These spindles are high speed only and should not be run at less than 8k minimum.

Are you not getting mixed up with the air cooled version, which has the minimum speed requirement to ensure sufficient cooling?

If Doddy has a water cooled one, he can run it at lower speeds, just don't expect it be be particularly useful, due to the correspondingly low power.

Ahhh, and dont run the spindle at 24k rpm. Or you will shorten its life considerably. In fact never run it more than 18k rpm. And then first run it for a couple of hours at slow speed so grease and bearing sets.

I don't regularly run mine at 24k, but I have done a few things which have involved running it at 24k for a few hours and in one case ~20 hours. It's 5 years old now and still OK, so I wouldn't worry for occasional use. You can check the bearing spec...