Hi

I'm about to build a cnc of 5ft by 5ft and I plan to use linear rail for the Z axis. The Z will be with a 2.2kW spindle , so let say about 9lbs with the bracket. I will cut alu from time to time too, but mostly mdf.

So is the MGN9c series could do the job, as 2 rail with 4 block OR a MGN12 (12mm) might be better. I'm not quite sure about how to get the proper load..

And for the "threadrod", it could be a 1605 ball-screw, but is there's a smaller one .. or if it's a good idea or just stick with the 1605.. ?
I'm looking to build it light, hoping to get same result as some other z axis with 16mm rod. Don't know if i'm wrong on this..

Thanks