Thor, or should that be Zeus?

[Chaz]

You mean 4kw direct drive spindles? Or belt driven BT and similar by 4kw motor?

Cause if first i dont see a reason why not to go with 4kw water cooled spindle. less than 400$ now that you have the drive. Bearings are cheap to change one day. What would bring the more expensive ones to the table that the Chinese one can not do??? for 1/5th or 1/10th the money?

But if i was to make it BT30 driven i dont see any option save servo driven. Why to put so much money and effort and not be able to do rigid tapping and similar??

Yep, at the moment the likelyhood will be either -

Just use a Chinese Spindle, I have the VFD already.

Get a BT30 Spindle, belt driven and use the same Chinese spindle to power it. This allows me some gearing options too.

Use the same BT30 Spindle and go AC Servo. Anything over 1.5KW needs to be 3 Phase and is fairly expensive. £1500 probably for a 4KW AC Servo and Drive.