Hi to all! It's my first thing uploaded there. I did it becauce I've face print quality issue. I found (as many of K8200 owners) that Z axis is weak. I doesn't move smootly and precise because of free play. Some people fix it by adding second leading rod or replacing threaded rod by trapezoidal rod. I found cheaper and faster solution. Nut and thread on the rod have some free play. Gravity force on the Z arm cancel it... but not enought when Z arm moving. I just add second M8 nut above stock nut holder with the spring beetwen them. Thingten additional nut to cancel free play and then assembled thing printed before. My holder dosent press on nut from top or bottom - it just prevent nut to spin You can see a picture of parts printed before (blue) and after (yellow) Gregor's advice ;) Bulding manual for K8200 doesn't mention this but I strongly recomend to dissasemble linear bearing and aply grease inside bearing. Machinery oil is not enought to guarantee long life and smooth moving. I did it also on threader rod as you can see ;) Have fun! Grzegorz "e_gregor" Made on my K8200 regular printer. Parts needed: 1) spring, 20-30mm lenght, 8mm internal diameter 2) M8 nut 3) piece of filament ;)