Hi Martin,
You will make a seperate plate that mount on your spindle.
This plate will have 2 dowel pins and a 8mm threaded hole.
You then attach this plate (with the spindle on it) to the Z-Plate (the tools steel plate)
The dowels match into the holes on this plate and the whole assembly is held together with only the 1 x 8mm bolt......sort of a quick release system.
Hope it makes sense.

Dowel pins are for mounting a plate for which you attach the spindle/router mount
Its sort of quick attach, two pins and a large screw in middle.

Something like this...

Attachment 12856

great, thanks s lot for the quick response!

First cutting test
 

Hi. I finally found some time during this summer to finish the machine to its cutting state. Finally its ready to make some chips! The cutting area is 1700 x 2900. The control system is LinuxCNC. I used Rick's gearbox to build 3:1 belt reductions. I had to slightly file it to fit it on the Z axis and it can be attached only to the first slot on top of the Y-car. Otherwise it works perfectly. I am using spindle Teknomotor 2.2KW with separated ventilator. However, there is still some work waiting for me, such as the e-stop wiring, controlling VFD via Linux, and so on. I will post more images of the machine and products done with it soon.

Congratz! Now the fun begins!

Cheers
Tim

Looking good, now you need some decals to be in line for the next serial number. :)

Sweet - back to back yellow MechMates :D

And the red beltbox is neat too. Nice job.

Well done...welcome to production land!

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.