Zaribo X axis lead screw conversion

thingiverse

These are pieces that will allow you to convert your Zaribo 3d printer's X axis from belt driven to screw driven. It may also fit other Prusa style printers, but you will need to verify the distance between the Z axis leadscrews and Z smooth rods to be sure. -The bearing holder is for mating to the MK3 style bondtech extruder holder. If you don't have this extruder, it's easily modified to fit another extruder holder by simply forming new screw holes in the bearing holder where you need it to mate to the extruder holder of choice. -This mod assumes you are using standard 8mm lead screws. I found the best selection on Ali Express. The ones I am using are 8mm diamater, 2mm pitch, 14mm lead screws. (the standard lead for Z axis screws is usually 8mm lead) The increased lead for the x axis screw allows the print head to move with the same speed that the belt driven system would without having to spin the motor too fast and risk skipping steps. You will need both the screw and the Tnut. I only found 14mm screws and nuts on Ali express, but an even more aggressive lead (16mm was the highest I could find) would further reduce the need for the motor to turn faster then with the belt system. Use the Prusa calculator to find the steps / MM value you will need to input into your firmware for the new xaxis steps/mm value. (if using 14mm lead screws like I am the value is 228.57) -You will need some (2) 608zz ,8x22x7 bearings. *disclaimer* This setup is experimental, and a first attempt. I've been running these models as uploaded for around 1.5 months, printing nearly non stop without issue. That said when assembling the axis it became apparent that either the models were not perfectly aligned in CAD, or the lead screw was not perfectly straight, or a combination of both. The offset was not drastic and the axis could be forced into true, however to accommodate and keep the Tnut from binding on the axis extremes (all the way to the left or right where the bend would be most prevalent) I had to loosen one of the screws mounting the Tnut to the x carriage bearing holder. This allowed the Tnut to align to the screw rather then the bearing holder. It sounds bad, but it makes no functional difference to the workings of the axis. The important part is that the Tnut does not move relative to the bearing holder. It's perfect alignment to the holder is irrelevant, so long as the Tnut is tightly secured to the holder. (I thought I would need to go back and mess with the models, but since offsetting the Tnut I've had no binding or printing issues, so I've left it be.) *another note* -Again, due to the slight misalignment in the screw, using a rigid coupling to attach the motor to the screw forced the motor holder to move along with the bend in the screw. I had to swap this for a flexible coupling to compensate, but it has worked just fine. -There are not holes pre formed for the Xaxis endstop switch because the screws used for that switch are so small. I just drilled and mounted it to the printed part after printing and assembly. You could do the same or add them to the model before printing. Parts list Lead screw *must find a Tnut with matching 2mm pitch and #mm lead* (I only found a matching pair in 14mm lead, otherwise I would have gotten 16mm lead) https://www.aliexpress.com/item/304-stainless-steel-T8-screw-length-500mm-lead-1mm-2mm-3mm-4mm-8mm-10mm-12mm-14mm/32695471104.html?spm=a2g0s.9042311.0.0.73bb4c4dYYWtUt Tnut https://www.aliexpress.com/item/T8-eliminate-clearance-nut-anti-backlash-nut-trapezoidal-screw-nut-pictch-2mm-lead-8mm-1pcs/32732745669.html?spm=a2g0s.9042311.0.0.73bb4c4dYYWtUt Bearings https://www.amazon.com/gp/product/B07216D1SZ/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 Other links Prusa Calculator https://www.prusaprinters.org/calculator/ Tinker cad project with Zaribo X/Z axis mock-up https://www.tinkercad.com/things/7QPhKkyIeCp