Promega Z-Belt Tensioning Rail Foot

This rail foot is designed for use with M3D's Promega 3D Printer, an open source platform. These feet give granular, metal-to-metal adjustability to the Tension of your 4 Z-Belts. Use of these on any machine is, of course, at your own risk. It may well be possible, with the 10mm of adjustability in the rail, to over tension the belts. Do NOT do this. That said, I have them on my machine at the time of posting and have tested them on several prints with great success.

So, why should you take any risk at all?

The Promega's stock belt driven Z-belt system can develop a bit of 'play' or ‘slop’ in it over time, and keeping your belts tightened properly allows you to keep the best accuracy in Z-movement. These allow you to do that without flipping the machine on its side by using a knob on the inside! That's the idea anyway. These may also prove helpful for bed leveling, but it’s not advisable to under or over tension your belts to get bed level.

Special credit and shout out to two M3D discord users who inspired this conglomeration of designs – Talryyn(John) and Predundant - both of whom modeled/released designs to the community, inspiring this reworked and somewhat combined version. If there is any individual who feels as if they have not given proper credit, or who wishes a different name/link be given, message me directly and I will work to remedy it ASAP.

---

Other Compatible Z-System Mods:
Replacing the mechanical Endstop with the Optical Endstop (available on the M3D GitHub from user Shadowhawk) is a highly suggested upgrade that can be used in tandem with these, and thanks to earlier input from discord user theBum - this rail foot also has a wire channel on the bottom. It is also very much worth getting theBum’s Z-fin slider for use with the Optical Endstop on your back right rail (available for download with Talrynn’s Rail Foot below).

As is mentioned above, this mod may be helpful in leveling the bed, but its purpose is to keep your belts tight and increase homing reliability. A modified version of C4’s Adjustable Z-Sliders may be used in conjunction with these feet – but the originals (as of 1/13/2019) leave a screw sticking out of the bottom that would ram into the top of these rail feet. If you do use them make sure the screw does not stick out of the bottom! (try the Remix available at the link below)

---

Links:
Shadowhawks Optical Endstop
https://github.com/PrintM3D/Promega/tree/devel/addons/ShadowHawk/Optical%20Z%20Endstop

Talrynn's Rail Foot and Fin slider
https://www.thingiverse.com/thing:3052677/files

Flat Bottomed Adjustable Z-Sliders
https://www.thingiverse.com/thing:3349785

---

If you run into issues trying to install/use this upgrade/modification, feel free to contact me at [email protected], on Thingiverse as tirelessirony, or on the M3D Discord channel also under the username tirelessirony.

If you appreciate this design and guide, consider donating via Paypal to [email protected] and/or to anyone of the fine users mentioned throughout. Such as, but not limited to:

• Discord User Predundant who designed the Swivel locking mechanism/slidelock rail shape (a.k.a. Dave Long, Thingiverse: supinemonkey - https://www.thingiverse.com/supinemonkey/about)
• Discord User Talyrrn(John) who designed a rail foot secured to the bottom via Screws/modeled the belt teeth (a.k.a John Mueller, Thingiverse: jwmueller - https://www.thingiverse.com/jwmueller/about)

---

The rest of the information/guide on print setting, finishing and installation instructions is available for download in the instruction document included. Cheers!