A new hope: Epoxy granite and steel.

[hardenum]

Jar Jar and Pippin are making some very valid points and If you are not careful you are going to waste a lot of euros.

You are over complicating the design around the spindle and underestimating the importance of precision required in surfaces, etc. The fact you haven't even considered or looked into Fixed gantry design or even understand how it works tells me that you haven't done enough research into what is required for the machine you require.

I suggest you STOP and go take a look at fixed gantry designs because it's the BEST design for the size of the machine you are planning to build.

I cannot build a fixed gantry, there is no way for me to mount the workpiece vertically if I went with a moving table. There would be no point in building any cnc if I can't mill all 6 sides of the work piece.

I have looked over hundreds of designs over the past half a year and only a moving gantry with a fixed bed with a cutout ala Datron allows me to mount the workpiece in all orientations.

There is another design, a horizontal cnc mill, that would allow me to mount the workpiece so that I can mill all 6 surfaces. But to be honest it looks quite daunting to go down that route.

The spindle choice is pretty easy though. One day your bank account is full, the next day it's empty. If I went with a motorized spindle, I'd be screwed if either of the components broke. Cartridge + motor is far safer if something were to brake and needs replacing.

I'm happy to be proved wrong though.

I was thinking of having the front mold piece machined instead of plates that are cast into the casting. Cast it after having everything aligned to the machined front mold piece. There is no way for me to transport the casting to a shop for machining after it's been cast.

By the way, I'm months, if not years, away from actually starting doing any of this work, so I really appreciate any and all insights!