TAZ Very loose Solid rod bearings?

I was just going over the TAZ we recently got, and noticed that the rod bearings were very loose on the rod. It seemed like I could slip a piece of paper in between the rod and bearing on one side. I specifically noticed this on the X-carriage. you could easilly wobble the carriage.

I know there has to be some room for sliding but this seemed excessive. Anyone else notice this? Perhaps a loose batch of bushings are out there?

It has been printing, but I doubt 0.1mm “print tolerance” accuracy is possible (like the specs call out for).

I’ll see if I can measure the gap somehow.

Here’s an improved double bearing holder, with some modifications to help retain the bearings: http://devel.lulzbot.com/TAZ/test_parts/double_bearing_holder/double_bearing_holder-2.0.stl. If you’re unable to print the bearing holders send an email to support@LulzBot.com and we’ll do what we can to help.

The machine came with the double bearing holder.

It’s not the holder that is loose…its the white plastic BEARING itself.

Is the gap between the smooth rod and the bearing or the bearing and the bearing holder? If it’s between the bearing and the bearing holder the new linked model should help.

Bearing and smooth rod. They all seem to be loose.

I’ve asked one of the guys in the fleet if they’ve seen something similar, They’ve noticed a little bit of play but it hasn’t affected the print quality. We’ll keep an eye on it and see how it proceeds. How much of a gap have you noticed? Is it measurable?

I just measured 0.3mm of “slop” on one of the bearings in the X-carriage…but if all of them are like this, that will quickly add up.

We’ve looked into the tolerances on the bearings, they are listed as: 0,032-0,075mm. We’ve worked with tighter IGUS bearings in the past and found that they’ve led to binding from too much friction. We haven’t seen a reduction in print quality in the 8 TAZ we are running in the fleet in comparison to the prints ran on the AO-101. It’s something we’re keeping an eye on in the meantime.

These bearings are clearly 3 times the tolerance specs you mention.
Can I get replacement bearings under warranty? Who do I call?

I can check the other bearings, but they also have a noticeable gap.

FYI, The rod measures 9.98mm

Are there higher precision ball bearings available?

If you don’t mind you can open a ticket by emailing Support@LulzBot.com, It’ll be the easiest way to get in touch with us.


If new bearings from Lulzbot don’t do the job. I was thinking of trying these out. http://www.realrecreationusa.com/p/10pcs-Lm10uu-10mm-Linear-Ball-Bearing-Bush-Bushing-10-19-29mm-For-Dia-19085616.html

But at that price, they are probably not that accurate.

One thing we’ve tried today is loosening the double and single bearing holder on the X-carriage. Squeeze them towards each other and then tighten them back. That pushes pressure against the bearings and still allows for smooth movement.

i will try that. it should help some

You noticed that too… Mine are *extremely loose… you can rattle my X axis quite a bit. I noticed this when I went to clean the nozzle and the whole bottom of the assembly moved… granted it has a bit of weight so it doesn’t move unless you try to move it, but there is lots of slop in the X axis bearings from what I can tell.

In looking at my 1 week old TAZ it has a double bearing on the top X rod, and a single on the bottom. Both are loose, but the bottom moreso than the top. Should the bottom bearing setup be a double as well?

And this isn’t isn’t the white bearing in the holder, it’s the white bearing on the shaft. There is probably on the order of 1/32 or more play between the white teeth of the bearing and the rods. I looked at the top one as well and it was better, but not by much… I haven’t even looked at the Z or Y axis stuff to see if they suffer from the same problem.

If the bottom of the X is supposed to be a double, how do we get another bearing?

Looks like I as well will try the squeeze test…


Tried the squeeze mod. You do have to hold the squeeze as you tighten all the bolts, but it is certainly better.

The bottom on the extruder just has one, not two, by design.

I’ve been getting very irregular layers and waviness in my prints. It seemed like there was excessive vibration with resonances. After reading this post, I checked my linear bearings and about half of them have the same problem discussed here. There is significant slop in two of my y-axis bearings and all three of my x-axis bearings. This seems to be a real issue – I’m going to file a support ticket.

Speculation, but if you read the data sheet these are designed as a press-to-fit part and as such the documentation says that they were will oversized in free state


Quote from the datasheet

Designed as a press-fit part, it will be oversized in free-state

Might the other 10mm versions that have the same outside dimensions be a better solution and closer tolerance? I doubt much pressing together is going to do anything for the tolerance issue, you are just expecting that stretching those tolerances against the outside of the 2 rods will address the issue, but unfortunately, that will only occur in one dimension…

Just a thought,

check the tightness of EVERY screw…i found several that were loose. They can loosen during printing too, I would re-check them periodically too.

Good catch, and that makes sense as to why they are all a little loose.

I did replace the 3 in the X-carriage with ball bearings, Since I added the extra weight of another extruder/hotend and wanted to reduce the friction. Nice and tight now. Might replace all of them with ball bearings eventually…I have noticed some hysteresis in the Z-axis, and excess friction certainly does not help that. The Y axis seems OK with these bearings though.