Missing Nuts on Rear Z-Axis - Anyone know part specification
 
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Jose Rivera
(@jose-rivera-2)
Active Member
Missing Nuts on Rear Z-Axis - Anyone know part specification

Hi all,

I received my long-awaited Core One yesterday, and its been a bit of an adventure setting it up. WiFi doesn't work on my machine, but I'll troubleshoot that later. my pressing concern is that my machine was shipped without the two retaining nuts for the rear Z-Axis trapezoid nut. As a result, z-axis calibration obviously fails. okay, mistakes happen, however I can't for the life of me get any M3 or M4 screw to take purchase, of any reasonable length. The nuts don't take purchase and fall straight through (M3) or fail to catch a tap for either size. It appears that the two screw holes were drilled but never tapped. its the only explanation as to why no screw will catch. Unless this is some proprietary screw, which I doubt.

Anyone else face a similar issue? any advice would be welcome.

for reference, https://help.prusa3d.com/article/homing-error-13301_401205 here you can see which screws are missing. (under trapezoid nuts, rear motor, first pic)

Posted : 04/03/2025 8:50 pm
Jose Rivera
(@jose-rivera-2)
Active Member
Topic starter answered:
RE: Missing Nuts on Rear Z-Axis - Anyone know part specification

Just to update any potential readers - I spent about 1.8 hours on live chat documenting the problem and submitted a ticket. the QA team will review and they'll get back to me. I'll update this post once they do.

Posted : 05/03/2025 3:00 am
ssmith and iftibashir liked
Jose Rivera
(@jose-rivera-2)
Active Member
Topic starter answered:
RE:

Update from yesterday - I have yet to receive any correspondence from Prusa indicating that a customer support ticket has been created, or any type of acknowledgment that the chat occurred once it was terminated. So I guess I'll just take their word for it that someone will get back to me. 

Some due diligence revealed a few things: 

1. The build plate doesn't have tapped screw holes, as I previously assumed. Watching Vector3d's teardown of the Core One on YT revealed that there are 3D printed parts that attach to the trap screw that serve as vibration dampeners and fasteners. My machine was shipped without this printed piece for the rear z-axis motor, as well as the two M3x14 screws. I attached a still of the video where you can see the part. I. believe it is this part: https://www.prusa3d.com/product/bed-spacer-rear/ I will try to print one on my Bambu and report back.

2. The Core One documentation and shop are woefully lacking for a product launch. There is no BOM or teardown instructions available anywhere, and the docs on the website are just haphazard at best. because this machine uses a lot of parts from MK 3 and Mk4, the docs link back to MK specific issues that aren't relevant for the core one. There is no Core One specific hardware kit available on the eShop, so I'm left to my own devices here...

I understand this ticket isn't old, but I was expecting at least some documentation or advice on how to troubleshoot. Straight radio silence from Prusa on the issue (no automated ticketing message at the least) was really surprising, and eye-opening as to what I could expect in terms of support going forward. 

This post was modified 3 weeks ago by Jose Rivera
Posted : 05/03/2025 10:55 pm
andhson
(@andhson)
Eminent Member
RE: Missing Nuts on Rear Z-Axis - Anyone know part specification

sorry to hear another example of obvious missing quality control.

It was not obvious how to navigate to the core one section for spare parts, it is still missing clicking on the start page but somehow I accidentally found it, if it helps any. https://www.prusa3d.com/category/core-one/

/Anders

Posted : 06/03/2025 7:44 am
altaic liked
mirek454
(@mirek454)
Eminent Member
RE: Missing Nuts on Rear Z-Axis - Anyone know part specification

Have you tried finding the part in printables for XL?

https://www.printables.com/model/449554-xl-printable-parts/files

Please excuse my writing style.

I am from the Czech Republic, I don't speak English, I translate using Google Translate

Posted : 06/03/2025 10:05 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Missing Nuts on Rear Z-Axis - Anyone know part specification

Probably T8x8

 8mm diameter 4 start, 8mm lead 2mm pitch

Trapezoidal thread 

Regards Joan 

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 08/03/2025 3:08 pm
LarGriff liked
Jürgen
(@jurgen-7)
Reputable Member
RE: Missing Nuts on Rear Z-Axis - Anyone know part specification
Posted by: @andhson

It was not obvious how to navigate to the core one section for spare parts, it is still missing clicking on the start page but somehow I accidentally found it, if it helps any. https://www.prusa3d.com/category/core-one/

Thank you for the link!

Is it normal that none of the spare parts in the shop links to the 3D model, for those who want to print their own parts? Is that just missing for the Core One since Prusa did not get around to it yet, or is it not provided for other printers either?

Posted : 08/03/2025 3:27 pm
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