Which linear bearings are used in the MK3?  

Re: Which linear bearings are used in the MK3?

Have a read here - https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/igus-drylin-on-the-mk3-t13612.html#p61022

Re: Which linear bearings are used in the MK3?

Thanks, then let me ask another question, what brands are good for LM8UU´s?

Like I said, I have bad rattling on bearings in the y-carriage and I want to swap them out for high quality ones.

Re: Which linear bearings are used in the MK3?

Not something I have every really looked into, but most seem to prefer Misumi. I would also perhaps look at offerings from known bearing manufacturers such as SKF. HTH.

Re: Which linear bearings are used in the MK3?

Lets say I want to get Misumi ones, I cant get them on their site, since they only allow registration for commercial resellers.
Basicly I cant get them that easily, which annoys the heck out of me.

Re: Which linear bearings are used in the MK3?

Same situation here. I can't order from Misumi UK as I'm not a business. I have seen them on offer on eBay, shipping from Germany though.

Re: Which linear bearings are used in the MK3?

High propability that its a fraud/imitation.
Why would they bother selling on ebay with a strange name?

And if those are bought and resold, I doubt that they are geniunes.

Anyway, I seem to just fixed the rattling.

Disassembled the y-carriage for the third time completly, rebuilt it and now the rattling is gone.

It werent the bearings which were bad, propably some sort of misalignent.

Re: Which linear bearings are used in the MK3?

your local bearing supplier may be able to purchase them for you!

regards Joan

Re: Which linear bearings are used in the MK3?

I had a rattling noise on the y-axis movement as well. Pretty annoying since the printer is now ever so silent.

I was able to hear the rattling when the printer was powered off and I merely moved the Y-axis (i.e. the heatbed).

ario.a stated that he fully disassembled the Y-axis multiple times and eventually got rid of the rattling.

With all information at hand, it became evident that the bearings are the source of the noise. So I performed these steps:

(1) Take away the heat bed by removing the 9 screws. No need to unplug any cable. Just slide it out if the frame and place it securely on a soft surface to prevent scratches.

(2) Now the nuts for the U-bolts are exposed. I unscrewed the nuts until the linear bearing was no longer held (didn't fully unscrew them) and turned the bearing very carefully a few degrees. Then fastened the nuts again (not too tight, as per the manual) and moved the Y-axis.

(3) I did this several times with all three bearings until the rattling disappeared.

(4) Re-assemble the heat bed, as shown in the manual.

It took some time, however not more than 30min in total, and not the rattling has gone. No need to replace the bearings.

Hope this helps

Cheers Alexander

Re: Which linear bearings are used in the MK3?

There is always Amazon Prime. If they don't live up to your expectation, send em back. Most people wind up finding a few good ones in any multi-pack, but I would agree its a bit frustrating. I did change my MK2 over to IGUS and brackets for my MK2 and I honestly can't really tell the difference with exception to the calibration and mesh bed leveling routines, and if I didn't know better, I would swear that they have added drag regardless o how carefully I installed them. Prusa sells a kit now for $13/10 and I would guess that they would stand behind them if shipping is not too prohibitive

Re: Which linear bearings are used in the MK3?

....... I did change my MK2 over to IGUS and brackets for my MK2 and I honestly can't really tell the difference with exception to the calibration and mesh bed leveling routines, and if I didn't know better, I would swear that they have added drag regardless o how carefully I installed them. .......

I think you should expect this. If you change from rolling friction to sliding friction you will add friction, worse there is friction that changes from static to sliding which causes disruptions. I think the only reason ball bearings fail to win comparisons100% is that they do have a rubber seal and this can drag. If it existed, a low-friction sliding seal on linear ball bearings would be awesome. If you remove the seals from the linear bearings they will probably perform better until they get dirty.

Re: Which linear bearings are used in the MK3?

I often think the bearing discussion is a boondoggle. There are legitimate times when a bearing is just bad or seized, but in most cases, I just think its something to fidget with and a distraction. More often than not, I think the bearing related conversations are misplaced and are really pointing to something out of alignment (or not following orientation instructions), but I think the nature and mindset of most of us in 3d printing today is that we are searching for perfection, and changing bearings is a reasonably easy thing to do. I have 3 MK2s and 2 MK3s with all different bearings from different batches, manufacturers, and types. There is little difference between any of them, but none are defective as I mentioned previously. All are working and oiled per their respective specifications.

Re: Which linear bearings are used in the MK3?

It took some time, however not more than 30min in total, and not the rattling has gone. No need to replace the bearings.

Your audible rattling may be gone, but I don't know if I'd go as far as to say "no need to replace the bearings" because the noise has subsided. I also have rattling PRUSA bearings, and as I actuate the bed by hand with printer powered off, I can absolutely feel varying resistance on the Y movement. It's significant and consistent, to the point that you can feel the bed subtly jerking each time you hear the various rattles. I understand the faulty 'soft rods' may also play into this, but I could hear this rattling directly after the printer was built, even before my rods had a chance to become scratched. These bearings are either faulty, or the stock bearings are simply of poor quality. Since many others have reported similar issues, I'm assuming the latter.

After reporting my issues, PRUSA promptly sent me replacement rods and bearings however I already have replacement MISUMI bearings and rods on hand, and I'm planning to use those instead. I'm waiting until PRUSA releases new X-axis parts before I rebuild the printer.

I plan on doing a handful of 'before and after' prints to see how much of a difference the bearing/rod switch makes, which I'll gladly share.