Replacement bearings recommendation  

Re: Replacement bearings recommendation

Just fitted some RJ4JP-01-08 igus bearings to my mk2s and now circles come out oval. Any ideas why? Belts and pulleys seems tight.

Igus bearings are less forgiving than the metal bearings, Y-axis rods must be perfectly parallel and the bearing cannot be over-tightened. But, if they are installed properly, they make the printer very quiet.

Thanks. I have a feeling it's due to the x-axis. Y runs very smooth

Re: Replacement bearings recommendation

Just fitted some RJ4JP-01-08 igus bearings to my mk2s and now circles come out oval. Any ideas why? Belts and pulleys seems tight.

Igus bearings are less forgiving than the metal bearings, Y-axis rods must be perfectly parallel and the bearing cannot be over-tightened. But, if they are installed properly, they make the printer very quiet.

I just installed these myself. Definitely noticed over tightening makes them worse. What did you use? I did zipties and Mk2s U brackets. Just felt repeatedly tested them throughout tightening process. My rods are slightly scratched from old metal bearings so that may be an issue as well.

Re: Replacement bearings recommendation

Just fitted some RJ4JP-01-08 igus bearings to my mk2s and now circles come out oval. Any ideas why? Belts and pulleys seems tight.

Igus bearings are less forgiving than the metal bearings, Y-axis rods must be perfectly parallel and the bearing cannot be over-tightened. But, if they are installed properly, they make the printer very quiet.

I just installed these myself. Definitely noticed over tightening makes them worse. What did you use? I did zipties and Mk2s U brackets. Just felt repeatedly tested them throughout tightening process. My rods are slightly scratched from old metal bearings so that may be an issue as well.

I used zip ties for the x carriage and these for the bed https://www.thingiverse.com/thing:1848700

Re: Replacement bearings recommendation

Anyone have recommendations for rods with the igus RJ4JP bearings? The stock ones seem to work but I think they are scratched from old bearings. Igus sells them on website but its more of a pain since im in the US.

Re: Replacement bearings recommendation

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Thanks. I have a feeling it's due to the x-axis. Y runs very smooth
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I use this https://www.thingiverse.com/thing:1846705 for the x-axis and use zip ties just to the point that they don't move. Do not tighten them up or they will definitely bind. You can add a little light oil the rods.

Re: Replacement bearings recommendation

Anyone have recommendations for rods with the igus RJ4JP bearings? The stock ones seem to work but I think they are scratched from old bearings. Igus sells them on website but its more of a pain since im in the US.

Lots of users including myself get them from Misumi, PSFG8-370, https://us.misumi-ec.com/vona2/detail/110302634310/?HissuCode=PSFG8-%5B20-800%2F1%5D&PNSearch=PSFG8-370&CategorySpec=00000028943%3A%3A370&KWSearch=PSFG8-370&Keyword=PSFG8-370&searchFlow=results2products&Keyword=PSFG8-370

Re: Replacement bearings recommendation

Although they will not fit in the X or Z carriages, I believe it will be fine for the Y bed frame.

I have to correct you on this. My prusa runs on RJZM-01-08 on both X and Y carriages without a glitch and without modifications.

Sorry to bring up the post again, but as the MK2S has U-Bolts to hold the bearings, do the RJZM-01-08 also fit? Its only 1mm difference against the normal RJ4JP-01-08 Bearings, but i am not sure if the RJZM will fit.

Re: Replacement bearings recommendation

I am running RJZM-01-08 for bed bearings. The U-thing has a radius of 16mm so it is a tight fit but works fine as I accidentally bought these. I would however not recommended the 01s as you will loose 3mm vertical build. Instead, the right bearing as recommended by IGUS is RJZM-02-08 which is a drop-in replacement for stock LM8UU linear bearings that came with the the MK2 and MK2S.

Specs for your enjoyment.
Stock LM8UU ID 8mm, OD 15mm, Length 24 mm

Re: Replacement bearings recommendation

I am running RJZM-01-08 for bed bearings. The U-thing has a radius of 16mm so it is a tight fit but works fine as I accidentally bought these. I would however not recommended the 01s as you will loose 3mm vertical build. Instead, the right bearing as recommended by IGUS is RJZM-02-08 which is a drop-in replacement for stock LM8UU linear bearings that came with the the MK2 and MK2S.

Specs for your enjoyment.
Stock LM8UU ID 8mm, OD 15mm, Length 24 mm



Be careful, on the igus site they specify that the bearing needs a steel housing in H7 or K7 in aluminum. This means it is not a compatible replacement as you need to add housing.

Re: Replacement bearings recommendation

@Greg
You are absolutely right, I've confirmed with IGUS that RJZM-02 does require a housing while the larger RJZM-01 does not. As RJZM-01 is 1mm too large in OD, IGUS has kindly offered to provide me with sample units to test and report for you all.

Re: Replacement bearings recommendation

Confimed too 😉

Use the 02 only with a housing, for example it fits good in the x-end idlers (z-Axis). There are some modifications on thingiverse to fit the igus very well.

Example : https://www.thingiverse.com/thing:2368502

I cannot confirm the 3mm lost in height, there is enough space left for full build volume.

Thomas

Re: Replacement bearings recommendation

I used 01 on Y-Axis because it made the most noise and no mod was required. You can make a rough calculation based on cord (gap) and diameter OD of bearing with loss of only 0.65 mm height from print volume going from 15 to 16mm diameter. But this is assuming perfect dimensions. h = 1/4 d sqrt(-(g^2 - 4 d^2)/d^2). Slot of 10mm being g in the equation. In the real world, the Y-carriage slot is smaller, and OD of bearing is slightly larger can be close to 1mm height loss. Where I lost the other 2mm is a mystery.

Re: Replacement bearings recommendation

Yes correct, thats theory.

I can go up to 204mm in z-axis.

Maybe your nozzle is too deep ?

Thomas

Re: Replacement bearings recommendation

I have completed my assessment of All IGUS bearings that have been considered viable by many on this forum. I want to thank IGUS for providing a set of all bearings listed below and am only saddened the results were not flattering to them. But, it is better to know and accept the trade offs than believe your own bias or print inferior parts due to misguided assumptions. As it is quite a chore to replace bearings central to operation of a 3D printer, I hope armed with the information here, you can avoid and or commit to such work for your modding queue.

LMUU8

RJZM-01-08

RJZM-02-08

RJ4JP-01-08

I hope this rests the myths and assumptions about IGUS bearing use in 3D printers. They are meant for CNC and other industrial applications where resistance to debris and long service life without lubrication is required. Silent operation is a side benefit from these traits and are not intended to be used in micron level precision movements necessary for FDM 3D printers. So, if you must sleep near you MK2/s, take the time and print 16mm adapted parts for the RJZM-01-08. But no, I cannot recommend either the RJZM-02-08 or RJ4JP-01-08 because you've just thrown your best-in-class printing quality out the window for a quiet machine.

Re: Replacement bearings recommendation

Nice one Steven! Very much appreciated! 🙂

Any chance you could show us the difference in print quality please?

Re: Replacement bearings recommendation

I've corrected the wording, no print tests were done. Report was gleaned from bed assembly only. Friction tests were by hand, sound was with a dB meter, slop was determined by yaw twist and digital calipers on fully reassembled printer for each bearing set. Print test would have been ideal but given the slop, I just lost interest when thoroughly disappointed with what I found. When I recover some piss and vinegar, we'll see a quartet of benchys.

Re: Replacement bearings recommendation

Oh I see. Thanks for clarifying.

Re: Replacement bearings recommendation

Hmmm. It seems that the others have posted a lot of bearing sources already. This one can serve as reference as well: metal machining services.

Although the downside on their bearings is it does not have any specs on it. I think it's modified to your needs, so you have to contact them for your desired specs, and would likely go the same way for your rods.

Re: Replacement bearings recommendation

so anyone ordered the misumi bearings have them shipped to Canada? It looks like it'll costs $30 just for shipping alone.

And did anyone install them in an mk2s?

Re: Replacement bearings recommendation

@gary
It couldn't cost that much from US to Canada.

@anyone with SKF
So I want to find out what the deal is with SKF and why they are so much more expensive. Misumi's seem to be smooth as butter from what I've seen online for Prusai...Pruseses? Whatever, clones and or Original but are still not silent. Are SKF any better at reducing noise while retaining glide performance?