I bought my Anet A8 somewhat 3,5 years ago and over time it got upgrade after upgrade until it became the work horse you can see here:
As you can see I converted it into a bowden style printer (fun fact: early low cost printers all where direct drive and got converted to bowden. These days all are bowden and get converted to direct drive), and added cable chains, x/y tensioner, an adjustable z endstop and other stuff.
However due to the original price which varied from around 95 euro and 150 euro depending on time limited offers, it´s frame was made from black acrylic, which required re-tighten every screw once in a while, resulting in breaking.
In my case it started at the bottom section where the four vertical pieces along the motors reside. Those started bending in or outwards and begin to crack. Since this printer is my ABS work horse and the ABS parts for my giant clock where done I continued printing ABS parts for the AM8 conversion.
This is the basic frame. It in fact is so robust now, that I added a handle on top of the bridge for easy transport from its chamber to the workbench and back.
After connecting the bridge onto the bottom frame with about 32 screws and beefy corner pieces it will never get loose again. This setup brings my printer on par with modern shaking bed printers available right now.
I made some minor changes to the original AM8 design, as I did not want to loose my existing parts for the X gantry (tensioner, adjustable endstop, cable chain) and the y axis (cable chain), I need to swap a few parts and design a replacement y endstop mount, so I printed one on the halfway converted printer: https://www.thingiverse.com/thing:4714278
Since I always use ATX power supplies I needed a proper AM8 mount for that, too. All I found were far to fancy and over engineered, total bullshit (big psu fan blowing over the build plate) or just perfect, beside the fact the mount it self was to weak in the result of making it look cool. Gnarf. So I designed my own, too. :AM8 ATX Power Supply Mount (Customizable) by geit_de - Thingiverse
Currently I print LED brackets for the sides, as printing inside the chamber without lights is just stupid. As you can see on the image the display is still loose, as I need to print a case/mount for it, too. Last part will be a camera mount for the RaspiCam. But those are details:
It is a beast now. A robust beast for the upcoming years to be. No more degrading as most structural parts are ABS and aluminum now and I bet the print quality is still on par with all recent printers you can buy.