New Spindle

[JAZZCNC]

You need at best a machine with at least 25 SBR or 20 Hiwin linear bearings to fully use a 2.2kw spindle for aluminum. ). 0.8kw spindle uses less power and will cost you 150eur +duty + 150eur for a brand inverter with shipping.

No not true at all I've built several machines that use the 2.2Kw running on 16mm rails. The rail size has nothing to do with spindle and everything to do with handling weights and loads of gantry and even the 16mm round rail easily handle most average DIY machine loads.
Where the round rail falls down with aluminium is the fact they are not accurate enough to hold tighter tolerances often needed when cutting aluminium, the actual size of rail is irrelevant.

The other benefit with 2.2kw is larger collet sizes so large shank tooling can be used which helps greatly with tool chatter in hard materials like aluminium. They are also useful if cutting woods and jobs were lots of material needs to be removed.

The rest regards VFD then I agree completely but must say the newer Chinese VFD's are getting much better and for the average user just cutting woods were exact spindle speed or power isn't critical they are fine.

[Boyan Silyavski]

No not true at all I've built several machines that use the 2.2Kw running on 16mm rails. The rail size has nothing to do with spindle and everything to do with handling weights and loads of gantry and even the 16mm round rail easily handle most average DIY machine loads.
Where the round rail falls down with aluminium is the fact they are not accurate enough to hold tighter tolerances often needed when cutting aluminium, the actual size of rail is irrelevant.
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Yeah,you are right. I was imagining the precision cuts with almost none finish work, the way i dream of.

Anyways for a correct answer the machine should be judged in its details and totality, cause there could be other weak spots which could make irrelevant or preferably the mounting of a 2.2kw spindle.

PS. I just advised the guy i am building a machine for to buy the 0.8kw spindle as he will run only 3d jobs with fine details due to the electricity cost here in Spain and especially when you pass over your home quote.

[JAZZCNC]

Silyavski I wasn't saying the 0.8Kw is not suitable or any worse than 2.2Kw just the larger spindle gives more flexibility.

If the machine is only ever going to cut with small tools then yes 0.8Kw will be fine and cheaper to run. Has you say the correct choice can only be found looking at the total picture.