Hello, what's your accuracy in your cnc. In the first picture it is not much 6mm and in the second 20mm. The screws are tight, everything is mechanically functional. How can I improve ?? Are you leaving it?
What controller/control software are you using. You might be able to get it better by calibrating your steps/mm - I'll attach a pdf that explains the principles and why it's needed. Couldn't see the whole vernier scale but you appear to be close. You shouldn't calibrate your machine by cutting something though - there are other factors that affect how accurate a cut is, including whether the bit is actually the size it claims to be, the material can affect how much the tool is deflected (there will always be some tool deflection even if it is so tiny you can't measure it), the material can be compressed instead of cut (a common problem with soft materials such as mdf) - even the difference between climb and conventional milling can affect the outcome. You will get the most accurate results if you cut things in two stages - leave some stock in the first toolpath (say 0.5 mm) and then remove that with a finishing path - the forces on the tool will be less with the lighter cut. Alex.
I use blackbox from openbuilds I do the G-code with the easel ptogram And for control I use the interface from openbuilds Mainly I cut 6mm in mdf I use a 1.5mm cutter
Openbuilds Control has a wizard for calibration. I don't use it myself as I don't have a grbl machine, but shout out here if you can't find it. Alex.