Central Z drive (Tevo Tornado, CR-10)

thingiverse

**Update March 30,2020**: I played around with this design... It turned out for now to have two weaknesses: - your lead screw and nut need to be of excellent quality. Sadly, this was not the case with the two parts I had; while printing the top piece for a standard nut, I faced the second weakness: - your Z lead screw coupler needs to have an excellent grip; sadly (again :)), this rles against the otherwise very good pritned coupler (https://www.thingiverse.com/thing:602481). Mid-print, the coupler slid from my motor and the entire gantry crashed onto the print bed. I also would not trust those original spiral couplers (they will be pulled apart on the med to long run). The way Z Axis is implemented always bugged me in my Tornado - raising a long bar on only one end seemed not really a solid solution for me. Ther eare many designs addressing this, by implementing a second lead screw. This in turn bears some downsides, for me the most significant was that I would not be able to use rear Z-Brackets anymore (I have not implemented them yet, but the possibility to do this is important to me). Again, ther eis a design incorporating Z-Brackets, but after a year of thinking I realized that I don't like the idea of being bound to this one and only implementation. Plus, these designs have a tooth belt at the top of the printer, limiting largely top-mounted equipment like spool holders. This particular design bases on the description a user "PetersHobby" posted in the German Tornado group on Facebook, please credit him for the original idea! My changes were some improvements: I made use of the V-Slot of our printers, so that the motor holder and the nut holder now fit the slot and therefore are attached even more stably (important especially for the motor holder, which will experienve variating torque because of the hotend moving from left to right). Additionally, I altered the lead nut holder to fit the nut I have. What you will need (Bil of materials): - Lead screw (you can probably use the original one, I went with [this][ls]. 500mm length should be sufficient, I will update the exact length once I have cut my lead screw. [ls]: https://www.motedis.com/shop/Dynamik-Lineareinheiten/Trapezgewindespindel-Zubehoer/Trapezgewindespindel/Stahl-Trapezgewindespindel/Trapezgewindespindel-RPTS-rechts-TR-8x15-L%3D1000mm::3953.html - Lead screw nut (I will upload a file for the original nut in the next days), I went with [this][tgmutter] one (it fits the lead screw above). [tgmutter]: https://www.motedis.com/shop/Dynamik-Lineareinheiten/Trapezgewindespindel-Zubehoer/Trapezgewindemutter/Trapezgewindemutter-Flansch-EBFM-Rotguss/Trapezgewindemutter-Flansch-EBFM-8x15-rechts-Rotguss::3739.html - Screws: * 5 x [M5x10 screws][m5x10] [m5x10]: https://smile.amazon.de/dp/B01H9I03IE * 5 x [M5x20 screws][m5x20] [m5x20]: https://smile.amazon.de/dp/B01IMHJNPK * 10x [M5 hammerhead nuts][nuts] [nuts]: https://smile.amazon.de/gp/product/B075WVRLDS * 4x [M3x40 screws][m3x40] [m3x40]: https://smile.amazon.de/gp/product/B018XL6VPU * 3x [M3x25 screws][m3x25] [m3x25]: https://smile.amazon.de/gp/product/B018XL6HKE * 3x [M3x16 screws][m3x16] [m3x16]: https://smile.amazon.de/gp/product/B018XL6434 - depending on the control box location, you might need an extension or a replacement for the motor cable. Printing works without supports (with the correct orientation, of course). I strongly recommend to use at least PETG and 50% or more infill, these are structural parts carrying significant weight. Attaching the upper part might be tricky, but I urge you to use all 7 screw holes, since this part will be carrying everything. Also, while it is not absolutely important to center the parts, you need to make sure they are aligned vertically. Misaligning them can break these printed parts because of the forces which will be tensing them. The holes for the M3 screws in the upper part are a bit too small, that's intentional. You will need to drill them with a 2.5mm drill and then tap the lead. I don't recommend not tapping at all, the holes are too long for self-tapping. The 3mm holes in the bottom are also too tight, you will need to use a drill (matching your screws) to get an M3 screw through them. Make sure to use the correct drill - these four screws will carry the weight of the Z-gantry, including the hotend. I recommend using a washer under the screw heads - the motor can get quite warm and the screw heads might get warm, too. Warm metal screwheads could force their way through the plastics...A washer helps to reduce this effect chance.