Leadscrew upgrade for Mendel90 Sturdy variant

This is a replacement pair of x-motor and x-idler brackets for use with T8 leadscrews and 4-hole anti-backlash nuts.

I made this because although I found STLs for several leadscrew upgrades on the internet none of them were quite what I was looking for. They were designed for the Dibond/kit variant which has different rod spacing or they were made for smaller leadscrews or 3-hole nuts or otherwise did not fit the printer and parts I had on hand.

I started with the original x-end.scad from the Mendel90 project on GitHub. I was attempting to make this a change which could be shared upstream so I added a new property to the config file, Z_screw_type so that the same file may be able to generate either set of parts. My intention was to make this work with all sorts of screws and nuts and all Mendel90 variants. Unfortunately, once I had it working with my own printer and leadscrews I found it difficult to motivate myself to finish the project as I still had many other upgrades I wanted to design. I still hope to come back to this however for now I will share what I have in case anyone else is looking to upgrade their Mendel90-Sturdy.

The modified scad file is included so you may try it with custom Mendel90 cofigurations. It might work. Or, if not perhaps someone would like to continue this work. For anyone who has a Mendel90-Sturdy and would like to replace the threaded rods with leadscrews the included STL files should work nicely.

Notes

• Even when configured for leadscrews these brackets still have the nut trap for the standard nut. This could be used as sort of a universal design for both.

  • The visible horizontal banding on the part in the photo is not due to a design flaw. It was caused by a crack in my original x-motor bracket which caused the brass nut to move in and out during printing. It was this banding, which at the time I thought was due to my original threaded rods or brass nuts wearing out which lead me to decide it was time for the leadscrew upgrade. I could print replacements without the banding now however I haven't found it necessary to do so.

Why replace your threaded rods with leadscrews?

I must admit I have not seen any huge increase in print quality since the change. I think I remember nophead writing in his blog that with the weight of the Wades extruder and a big motor backlash isn't really an issue even with a simple nut and a regular threaded rod. Sorry, I don't want to go find the quote today. Sorry if I got it wrong! Anyway, this seems to be true although I have since switched to a lighter Titan extruder and smaller motor. Maybe it matters now? I don't know because I switched to leadscrews first.

So what are leadscrews better at? Leadscrews can be moved faster. But speed on the Z-axis doesn't count for much during printing since it only has to move once per layer.

So here's where it really counts. Homing speed. Waiting for the carriage to travel from the bed to home and back to the bed used to take forever with ordinary threaded rod. Don't ask me why but the time of day that I tend to start thinking about starting a print and the time of day my wife decides to prepare dinner frequently coincide. So many times she has yelled up that food is getting cold while I have shouted back that it will only be "another minute" (yah right) I just want to get this print started.

Leadscrews may have saved my marriage. So get a pair yourself, print this adapter and save yours too.

This design was based on:
- The Mendel90 RepRap by nophead (https://www.thingiverse.com/nophead/about)