Someone on YouTube stated that machines like that would bend like bamboo under load (in a politely way, it's obviously somebody that knows about the "qualities" of cheap machines). My CNC v3.2 is a solid build with a weight of more than 60kg. To demonstrate the capabilities of the prototype I have carved another test piece of aluminium at the end of my video about the mechanics (starting at 9:37):

The result looks promising:

Have a look at the full resolution image.

To get that result I have used a 3.2mm router bit and added a continuous flow of water. The circle goes from the router to the bowl underneath the router table into a bucket under my workbench, from there into a watering can, manually into a reservoir on top of the machine and finally back to the router. The pump I had in stock for many years was obviously broken...

Something that bends in fact like bamboo is the cheap router motor with it's plastics housing. which results in deviations that are visible in the test piece at the starting / end points. Have a close look at the bottom left of the square and the triangle and at the top centre of the circle. Nonetheless the straight edges of the square and the triangle are great (considering the low tech configuration currently in use). The dimensions of the shapes hit those of the template with an error of less than 0.1 mm.

More citizen science must follow to express the quality of this machine in numbers. It's the only way to find the weak points and so to improve the design.