Tr8x8x2 no-backlash nut for Wanhao Duplicator 7

thingiverse

I strongly dislike backlash in all its forms. Sometimes, it can be easily compensated for by a thoughtful design and construction approach. However, other times backlash compensation could lead to something that is either not useful or even generates more problems than a good operation. Don't waste too much time arguing about the Wanhao Duplicator 7 leading screw and nut. Having a mechanism that provides hundreds of microns play when you're looking for tens of microns layer height just doesn't make sense to me as an engineer. You can find attached both the STL file that I printed and works, along with the OpenSCAD file to generate your own. The issue is that you cannot find (or at least I couldn't in a reasonable time) any specifications for the geometry of the thread. All you know is that it's 8 mm outside diameter, 8 mm pitch trapezoidal thread with 4 starts. I'm not even sure if the designation used in the filenames is correct. Anyway, it works. It is designed to reuse the backlash nut as a supplementary means of prolonging its life by wearing down. It is longer (40 mm) than the original one since there's enough space under the build plate bracket and there's a longer thread for better guidance. You may use any good material for this purpose, such as igus, POM (Delrin), or nylon. I started with PLA, which is true to its performant reputation from Sakata3D based on Ingeo 3D870 material. *Update March 16, 2018* 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. The old version is still kept for reference. No longer a work-in-progress since 2 of these nuts have been working for weeks now with [The Black Brothers](https://www.thingiverse.com/thing:2749567).