Printing like paradise


The steel bearings are louder than the brass, but on my printer not so loud that I worry about hearing damage or anything like that.

You are not forgetting to apply light machine oil to the rods. are you? Maybe you have gotten some poor quality or damaged bearings? Something doesn’t seem right about that…


@shelxle just measured the ES flags from Velleman Vertical Slider - they are 3.25mm thick. Anyway, just printing and testing ES with 2mm flag.
I wonder why your slider is tilt. Did you use wire or zip-ties to fasten the bearings? Maybe (one) of the bearings didn’t snap in properly…

Just tried the whole calibration again:

M665 H330
G33 P1 ; calibrate Z axis

The G33 P1 results in “.Height:317.01”, the G33 in “Height:317.03 Ex:+0.00 Ey:-0.04 Ez:-0.05 Radius:107.65”.

Maybe you want to log the complete process via serial console to see what happens…


Just pushed the latest version. Now the repo contains a K8800-ESv2-7.5mm.stl endstop - 2mm width.


The Calibration is not the issue. Everything works fine but after calibration the nozzle will not move to the desired position if the firmware DELTA_HEIGHT is smaller than the final calibrated value.

@Dr_Vegetable I have now installed LM10UUs again fixed with one zip tie on each (used my Dremel so it fits well) Sound problem is gone now :ear::+1:
Now test printing…


I also saw this with the original Velleman Firmware. I guess that‘s the reason Psycho set it to 330mm.


@SusisStrolch Thanks for your slider version! I printed it, and here are my observations:

  • I had HUGE problems fitting a normal electrical zip tie to it, because I didn’t have enough black ones. Even the black ones were a real pain to put into place, it was just too tight. I warmed the piece up and then got the zip tie through
  • The bolts forms under the bearings cage is too tight. A few 0.1mm wouldn’t hurt imo

But now:
I have decided, dunno why to upgrade this part. I had a few spare LMU around so I guess that’s why I wanted. I just made the first slider on place. But I stopped before taking the two next ones. What’s the real benefits of the bearings vs the stock brass ones? The LMU10s make a huge noise (ok, in comparison to almost no sound with stock ones), that’s all I found as a difference, as I did not yet take the others off and my printer is still dismembered :slight_smile:


Too tight in general or only on the outer side? I used small ties for electronical use. Only prob was the entry on the outer side, where I used a screw driver to widen the entry a bit.
(Sorry, onsite at customer til WE, so I can’t tell the exact measure of zips)

I will increase the clearing distance again - mine went in w/o any problems. I’ll increase the cld for the nuts.

I’m using the IGUS RJ4JP - they are self lubricating and much lighter than the LMUs. They are even lighter then the brass ones - and I only hear the sound of the steppers.
So, my personal advantage is

  • less noise
  • no lubrication required
  • less mass of the whole actuator
    Printed nearly a whole reel PLA w/o any oil…


The intended benefit of switching from the brass bushings to LM10UU is to reduce friction and eliminate the break-in period for a new K8800.

If you have converted one tower to LM10UU and you still have brass bushings on the other towers, you should easily be able to feel the improvement just by sliding the towers around. I have two K8800’s, one with LM10UU and one with brass bushings, and the difference is night and day.


I had also the problem that the excess oil somehow made its way into the LCD as you can see here:

the lower left region has now a different shade of blue than the upper right corner.

And there is always the black thing on the rod. Which is not there for Drylin or LM10UU.


Well, one good point for the bearings is that you use bearing grease, which is much better than oil. But linear bearings are louder than brass. The question was mainly: Does it really improve the prints quality or anything else?

@SusisStrolch Too tight in general
@Dr_Vegetable I meant, I stopped after mounting one, wondering if I should do the other 2 as well. The brasses are broken in so they feel really adjusted. Of course, they won’t ever stop making the oil turn to black, it’s totally normal. But the bearings sound louder to me. I’m just wondering you know, I guess I could just try. But I want to reprint the sledges first so I’ll try in a while, first re printing on the other printer

@shelxle Had exactly the same happening on the first printer. Since then I have kitchen paper folded around the shafts bases, no more leakages :slight_smile:


I did that but I forgot to fix it with some kitchen rubbers. My room is also not a dust free laboratory. I do not miss the brass bushings.


@Psycho can you elaborate a bit on this?
I understand that nutcatch and and holethrough are close to the limits, depending on your filament, temperature and printing orientation.
Some of this are related to the libs I use (I’m able to fix them if I know what to fix).
What’s about the bearings? Are they also too tight?
I always check the clearings before submitting the changes.
F.e. if a nut fits w/o pressure I assume it as ok…


I use PLA from REC, 1.75mm, printing at 200°C through a 0.35 mm nozzle. Orientation was Z tower sledge orientation 180° Z rotated (bearings in front). I used the settings you gave on your repo to print

The bearings fit very nicely, they nicely click in and stay there. The nuts, well, I broke a piece in 2 by trying to push one in. Using the stock nuts.


@Psycho: Just pushed a K8800-BB-LM10UU.stl single bearing block to check the clearing distance for the MC-cup nut.


I had also the problem that the excess oil somehow made its way into the LCD

Don’t try to wash it in any way, I managed to make my LCD even worse that way and had to get a replacement from Velleman because it was driving me nuts. I think you can remove the oil by soaking it up with paper towels and when reassembling put some cotton wool on the bottom to absorb the excess oil.

I also would have concerns about using LM10 bearings on the stock rods, they are not hardened I believe and are way different than typical linear motion shafts. I could easily scratch the outside of them with sandpaper (mine had a blemish from mishandling I believe) and this leads me to think they are not nearly as hard as a properly induction hardened linear shaft designed to work with linear ball bearings. This probably means that the balls in the bearings are harder then the shaft.

Using a drylin bushing is a great idea however and I might switch to them myself but honestly the brass bushings are not that much of a hassle to me, I lubricate them very sporadically after the break in and I think that the friction they provide is not at all a problem. As for the noise… well there is only so much You can do with DRV8825 stepper drivers… I have to ask Velleman to provide the PCB files someday and put standard step-stick headers on them for better options like the Trinamics which are havenly quiet.