Help me choose my first spindle

[routercnc]

Hi Desertboy,

You might be mixing things up in your post, not sure. So here is my understanding of how it works and what you need. Water cooled spindle is not like a router. You need a VFD (invertor) to connect it to which is why that ebay link shows them as bought as a package.

The speed control is done inside the VFD and can either be:
option 1. Via buttons on the front panel (tedious, but works to get you going)
option 2. Via an external 10k pot wired to 2 special control terminals under a small cover on the VFD (this is very cheap and simple to do so don't worry about that for now)
option 3. Via Mach3 which talks to the VFD through an interface board. This can be added later so again don't need to worry about it in terms of spindle selection. My understanding here is that this can be PWM signal or a 0-10V signal.

Spindle power should be at least 1.5kW (although I think Boyan has used 0.8kW for certain applications?), but ideally 2.2 kW. You get more power/torque which helps at lower speeds as these things are direct drive and they will stall out if you push them and the rpms are low. But the main reason for going 2.2 kW is that the collet is ER20 instead of ER16. This means it will take tools of up to 12mm instead of ~6 mm which is a big bonus. 6mm to 8mm or even 10mm is a big increase in tool stiffness so will help with the roughing out. I've heard 1.5kW can occasionally come with ER20, but I would go for the 2.2kW anyway.

I can't help on the German bearing quality question but I suppose the reality is you either take a punt on these generic Chinese machines, or save up (quite a lot!) for the HSD Italian type stuff.

I also started many many years ago with a router on the machine and it is very noisy, plus I suspect the run out on the collet way more than 0.05 mm, and the duty cycle on a router would not like running the extended jobs a CNC machine will typically run for. If you are in any way serious about a CNC machine give them a miss. Same goes for the Kress spindles.