Taurus Z axis for Prusa MK3 and MK3s

by jltx Jan 3, 2019
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For me the lash was slicing (with a .4 nozzle and .42 extrusion width) as a single line for he thin parts that did not join with the other perimeters and so the pieces break very easily. What should I try to change in my print settings?


Edit: just solved my own problem. Counterintuitively I had to disable detect thin wall and it worked great.

2 threaded rods: 5/16" x 15" or 8mm x 380mm

Can you direct me to a link to order this rods? I couldn't find the right size online.

Hi, I was wondering what effects did this mod have directly on print quality/speed? Also is ABS a suitable material for this print?

I've used your PSU support and its great. Thanks.

Honestly hard to say. It was my last upgrade and by that point everything was already printing pretty well given my other mods, especially skelestruder. I haven’t been printing tall objects often which is where I think this would help more.

You could try abs but keep it mind it shrinks slightly (anisotropically too) so may be tricky to get everything to fit properly.

Are the motor mounts compatible with the stock z-tops?

The Y-axis threaded rods on the MK2 were M10x350mm. Would it be possible to remix this so those could be used instead of the M8 rods your design specifies?

Sorry, missed this earlier it appears. I will add that to my list to investigate. 350 is a bit short so coupling may be a challenge. But M10 is stiffer which is good.

I would also like to know this because I think my next upgrade is going to be the Taurus. I have a bunch of parts left over from my MK2 and would love to be able to use the leftover rods instead of them just collecting dust.

All assembled! Observations:

  1. The nut hole on one z coupler broke while tightening, see pic. The printed orientation of the parts makes this area a bit weak. Tighten with care.

  2. I think that due to the design with captive M8 nuts at each end of the rod, it's really hard to reliably get everything assembled with zero deflection. As far as I can tell, to adjust the rod length, you can either a) rotate the rod coupler one full turn around the rod prior to fixing (rather coarse) or b) remove the rod coupler, remove the captive nut and reinsert rotated by one or more facets, then re-assemble (very fiddly). Even then, slotting the z coupler around the z top is a snug fit which causes deflection - so in the end it's really hard to asses how much deflection is finally applied. So in the end I didn't use the captive nut in the z couplers (see pics), and this allowed me to have the rods set up with loose nuts above and below couplers, with the rods free moving in the couplers when the z frame is deflected. Then carefully bring lower nuts up to coupler, then tighten top nuts down onto coupler. The top nuts don't sit flat due to the coupler design, so it would be good to slightly change the design so that a nut & washer can sit flat there for those who want to use this fixing method (captive slot could remain for those who prefer it).

  3. The slot mount design is superb!

  4. While the crossbars likely to add some stiffness, they are not a silver bullet. There's still visible flex when manipulating the frame with moderate force, in the horns and the z tops (I am using all lashes). Of course, we need to resist small transmitted vibrations rather than substantial sustained forces, so we'll see. Next thing is to print an XYZ test cube - I'm hoping for reduced ghosting.
  1. Interesting. I didn’t have any trouble there. I’ll look.

  2. Yes, but you only ever do this once so I don’t see the issue. Rotate the nut as you say so the rod rotates without play, then tighten two nuts. Done. If you need to remove rods for some reason, the critical nuts are captured and you won’t have to readjust. Just tighten down loose nuts again. I think it’s better.

  3. Thanks.

  4. Agree. This is really for taller prints. I don’t expect much difference for a calibration cube unless you had some resonance.

Lash parts and wedge doesn't print on 0.6mm nozzle. Why go befier on main parts and then extra small perimeters on small parts?

Because those parts need those dimensions. Lash has to bend. I can upsize it a bit though

Bend can be fixed if printed with ABS since it can bend much better than PLA or PETG

Hey! I came across your design while looking for parts to upgrade my MK3 and it looks awesome! Is it possible to get a few photos or CAD drawings (if any) of the assembled axes, though, just to compare notes? I can't figure out what the final image will be once complete. Stoked to try them out!

I am working on get my prints done now. I was waiting for some new filament to show up but turns out its backordered. So plowing ahead with what I have. I hope to get pictures up soon. The main mounts are the same as stock, just beefier. The cross member connects the Z top to the front of the frame base to stabilize it. You can add it at a later time since it Is modular.

I posted a couple pics