This will be interesting. I will be following the progress since I am doing something similar. I am doing this: K40 12x24in rebuild (In Original Case) but with some modifications. I have a Cloudray laser head that needed a custom 3D printed piece to hold it in the right position, so I added a couple of holders for two line lasers for an aiming crosshair. In fact, my order for the parts I need from Openbuilds just shipped today.

 

I use metric as well. The math is so much easier. In my mind I can picture what 0.5 mm is, my brain just can't wrap around dividing an inch into 1000 smaller increments.

 

If you download the step file provided, open in Fusion 360, and change the units to mm you can get what you need. I do everything in mm so mine is already converted, but I modified it so there are differences vs. the original. Now I just need to finish it. I actually dropped the assembly yesterday and broke 3 3d printed parts. I guess that is better than dropping the laser tube.



Or, use Googles mm to inches (works backwards too)