Martin,
Nice yellow machine, you will not hit yourself when you walk around in the dark in you workshop. These are the first pictures I see from the gearbox. and they look nice in Red. 2 questions,
1) could the laser cutter made the hole for the bearing with the correct tolerance?
2) This one is not a question but a request, is it possible for you (sooner or later) to update the gearbox design for the original z axis at the gear box topic on the forum. then the story is complete.

Look locally, they are the simplest of bearings. Almost the same size as a kids roller blade center. I purchased mine from vxb in california, but the part linked to a skate as a replacement part number.

Thanks for the nice comments.

Rik: The gearbox plans worked great, the bearings fit in just perfectly. I used your design also for the z axis. However, it fits only when you put the z axis in the first slot of the Y car, as you can see on this picture. If I find later that I need to move it close to the center, I will redesign it and post the plans here, but I think that the air hose should fit in still fine.

I still plan to work out more the LinuxCNC, pragram to it spindle control and so on, and than post the files here.

Also, I want to make now a dust shoe. I like the one from Ross aka Surfcnc, but I did not see anywhere that plans to download, but I can probably trace his jpg image in autocad.

I reckon you don't need the gear reduction on the Z-axis. Consider how often it move during cutting... Direct drive should have more than enough precision for plasma works.