Z-axis threaded rod causes layer skipping *Please Help* Problem: Some places on the M5 rod the nut is harder to turn, the rod also seems a little bent, the top of the rod is moving approx 5mm from side to side. Because the nut is harder to turn at some places, the Z motor seems to skip a layer because it thinks that it has moved. Big blobs were created when I tried to save this print, sometimes the Z axis wouldnt go up because the nut got stuck, so I paused the print and raised the nozzle 0.2 mm but it didnt help at all. Video showing when the Z axis skips small steps: [www.youtube.com] The results of layer skipping (after 3 hours print time) notice how the first layers are perfect (by my standards) and the rest turned into some goo 4EITybp.jpg mod_embed_images_loadimage('c99f6fc2ec3d5114957a07b93d41d805', '/forum/thumbcache/7d2/8d4/b40/a19/316/b1c/d22/ab6/3e4/468/0b_800x400.png', 'http://i.imgur.com/4EITybp.jpg', 'https://reprap.org/forum/addon.php?340,module=embed_images,check_scaling=1,url=http%3A%2F%2Fi.imgur.com%2F4EITybp.jpg', '', 395012, 800, 400, 'Loading image ...', false); the rod/nut seems to wear down on the parts where the nut was hard to turn unoGYCv.jpg mod_embed_images_loadimage('c48cb10430fb89ed1116060377d39406', '/forum/thumbcache/60c/501/f03/87f/2de/ce2/d24/892/f97/0c7/43_800x400.png', 'http://i.imgur.com/unoGYCv.jpg', 'https://reprap.org/forum/addon.php?340,module=embed_images,check_scaling=1,url=http%3A%2F%2Fi.imgur.com%2FunoGYCv.jpg', '', 395012, 800, 400, 'Loading image ...', false); Possible solutions: Change the nut (and/or) the rod Print an top mount for the z axis Z_Axis_Top_preview_featured.jpg mod_embed_images_loadimage('ec1672d09a62deb2b146fb23e57d30cc', 'https://reprap.org/forum/addon.php?340,module=embed_images,url=http%3A%2F%2Fthingiverse-production.s3.amazonaws.com%2Frenders%2Fd0%2F8b%2F81%2F3e%2F1a%2FZ_Axis_Top_preview_featured.jpg', 'http://thingiverse-production.s3.amazonaws.com/renders/d0/8b/81/3e/1a/Z_Axis_Top_preview_featured.jpg', 'https://reprap.org/forum/addon.php?340,module=embed_images,check_scaling=1,url=http%3A%2F%2Fthingiverse-production.s3.amazonaws.com%2Frenders%2Fd0%2F8b%2F81%2F3e%2F1a%2FZ_Axis_Top_preview_featured.jpg', '', 395012, 800, 400, 'Loading image ...', false); - Possibly change the gears 20140203_123805_preview_featured.jpg mod_embed_images_loadimage('e43cbf87ffdd15b0e3be7c037be43528', 'https://reprap.org/forum/addon.php?340,module=embed_images,url=http%3A%2F%2Fthingiverse-production.s3.amazonaws.com%2Frenders%2Fc5%2F98%2F48%2Ffc%2F04%2F20140203_123805_preview_featured.jpg', 'http://thingiverse-production.s3.amazonaws.com/renders/c5/98/48/fc/04/20140203_123805_preview_featured.jpg', 'https://reprap.org/forum/addon.php?340,module=embed_images,check_scaling=1,url=http%3A%2F%2Fthingiverse-production.s3.amazonaws.com%2Frenders%2Fc5%2F98%2F48%2Ffc%2F04%2F20140203_123805_preview_featured.jpg', '', 395012, 800, 400, 'Loading image ...', false); https://reprap.org/forum/read.php?340,395012,395012#msg-395012 Wed, 12 Aug 2026 10:39:34 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?340,395012,399693#msg-399693 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,399693#msg-399693
Quote
Amsterdamman
Anyone using the herringbone gears shown in #3 photo above?
[www.thingiverse.com]
They seem a better system.

I do, as do many others. The original ones in my case a bit of backlash (some play when they rotate, you can basically wiggle one of them back and forth a bit without the other moving). While it was small, it could potentially have some effect when doing auto bed levelling and the Z axis moves back and forth a lot. Also they look cool.]]> jstck Ormerod Wed, 27 Aug 2014 07:21:02 -0400 https://reprap.org/forum/read.php?340,395012,399655#msg-399655 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,399655#msg-399655 My first simple solution was to add a flat piece of kapton tape the end of the Z threaded rod's nut and then jam the tape end into the gear hole.
Also bought a new steel threaded rod yesterday and ordering the brass nuts.

Anyone using the herringbone gears shown in #3 photo above?
[www.thingiverse.com]
They seem a better system.]]> Amsterdamman Ormerod Wed, 27 Aug 2014 05:44:44 -0400 https://reprap.org/forum/read.php?340,395012,398271#msg-398271 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,398271#msg-398271
(I also fixed a problem where the nut on the threaded rod moved when going up and down on the z axis, I simply put a piece of paper between the nut and the printed part and the nut is no longer moving when the z axis is making small steps up and down.)

Solution:
Change the M5 threaded rod preferably rust-free steel
Change the M5 nut Preferably a long nut like this one:

Lubricate the m5 rod/nut with some lubricant for engines/bikes/hinges, it will decrease wear on the rod.
I bought "Hamron Multi Lube" its basically for everything mechanical, you can buy it (or something simular) at a gas station.
]]> victhor Ormerod Sat, 23 Aug 2014 14:14:12 -0400 https://reprap.org/forum/read.php?340,395012,395278#msg-395278 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395278#msg-395278 like this.

Quote
bitfield
Not sure what the tool is called or where to buy it but I can sort that out if you want.

I think you're talking about a die.]]> DaveB Ormerod Fri, 15 Aug 2014 13:30:13 -0400 https://reprap.org/forum/read.php?340,395012,395253#msg-395253 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395253#msg-395253
Dave
(#106)]]> dmould Ormerod Fri, 15 Aug 2014 12:10:00 -0400 https://reprap.org/forum/read.php?340,395012,395244#msg-395244 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395244#msg-395244
Dave
(#106)]]> dmould Ormerod Fri, 15 Aug 2014 11:44:48 -0400 https://reprap.org/forum/read.php?340,395012,395079#msg-395079 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395079#msg-395079 ezwul Ormerod Fri, 15 Aug 2014 02:49:28 -0400 https://reprap.org/forum/read.php?340,395012,395077#msg-395077 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395077#msg-395077 You can increase the voltage to the stepper slightly which should stop the missing steps.]]> VortyZA Ormerod Fri, 15 Aug 2014 02:44:40 -0400 https://reprap.org/forum/read.php?340,395012,395073#msg-395073 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395073#msg-395073
Probably one of them had some section of crappy thread or some dirt that caused it, or maybe it wasn't lubricated, but with that amount of metal shavings coming out both are probably badly worn by now.

Mine wasn't nearly so rough as to cause the motor to skip, but it was making a lot of noise and had some metal shavings come out of it. I replaced it with a stainless steel threaded rod and a long brass nut, which has worked perfectly (with the rod being harder and the nut being softer than the original parts). It still needs to be kept lubricated and clean though. Thin lubricating oil does work, I use PTFE spray since it attracts less dust and dirt.

As for the other two proposed things, they won't help with this specific issue. The top mount can be of use if the rod is a bit bent, and replacing the z drive gears mainly reduces the backlash in the original ones (which might matter if you do z bed levelling but not very much otherwise).]]> jstck Ormerod Fri, 15 Aug 2014 02:29:53 -0400 https://reprap.org/forum/read.php?340,395012,395067#msg-395067 Re: Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395067#msg-395067 Not sure what the tool is called or where to buy it but I can sort that out if you want.]]> bitfield Ormerod Fri, 15 Aug 2014 01:48:50 -0400 https://reprap.org/forum/read.php?340,395012,395012#msg-395012 Z-axis threaded rod causes layer skipping *Please Help* https://reprap.org/forum/read.php?340,395012,395012#msg-395012 Problem:
Some places on the M5 rod the nut is harder to turn, the rod also seems a little bent, the top of the rod is moving approx 5mm from side to side.
Because the nut is harder to turn at some places, the Z motor seems to skip a layer because it thinks that it has moved.
Big blobs were created when I tried to save this print, sometimes the Z axis wouldnt go up because the nut got stuck, so I paused the print and raised the nozzle 0.2 mm but it didnt help at all.

Video showing when the Z axis skips small steps:
[www.youtube.com]

The results of layer skipping (after 3 hours print time) notice how the first layers are perfect (by my standards) and the rest turned into some goo


the rod/nut seems to wear down on the parts where the nut was hard to turn


Possible solutions:
  1. Change the nut (and/or) the rod
  2. Print an top mount for the z axis


    -
  3. Possibly change the gears


]]> victhor Ormerod Thu, 14 Aug 2014 19:27:05 -0400