Tr8x8x2 no-backlash nut for Wanhao Duplicator 7

thingiverse

I don't like backlash at all. Sometimes it can be compensated easily with a careful design and construction. Some other times backlash compensation could lead to something either not useful, or even something that may generate more troubles than a good operation. Don't really spent too much in arguing about Wanhao Duplicator 7 leading screw and nut, but having a mechanism that provides some hundreds microns play when you look for tens of microns layer height, only this alone cannot fit my engineer mind :) So, you can find attached both the stl file that I printed and works and the OpenSCAD file to generate yours. The issue is that you cannot find (or at least I can't in a reasonable time) any specifications for the geometry of the thread. All you know is that is 8 mm outside diameter, 8 mm pitch trapezoidal thread with 4 starts. I'm not even sure that the designation used in the filenames is correct. Anyway, it works. It is designed to reuse the backlash nut, just as a supplementary means of prolonging the life shortage by wearing. It is longer (40 mm) than the original one since there is enough space under the build plate bracket and there is longer thread for better guidance :) You may use any good material for this purpose, as igus, POM (Delrin), nylon. I started with PLA, is true a pretty performant one from Sakata3D based on Ingeo 3D870 material. *Update March 16, 2018* Ok, after checking the first design and some debates on the Facebook groups, I decided to go 100% on the safe side and create an "inversed" version of the nut. Read in the **About backlash** section why this could be beneficial. Old version is still kept for... reference ;) No longer work "in progress" since 2 of these nuts are working for weeks now with [The Black Brothers](https://www.thingiverse.com/thing:2749567).