I've been reading into this linear bearing replacement and wonder what if anyone has

I’ve been reading into this linear bearing replacement and wonder what if anyone has tried to use this one in lieu of ball bearing type? thx

Seems to me it will be quieter, no need for lubrication and I think it even has less friction… Well at least that’s what they claim…

I think that those are the ones that are 1mm bigger in all directions than an lm8uu

how much they cost ?

The RJ4JP-01-08 are drop in replacements for lm8uus.

Lots of people use IGUS bushings/bearings both in reprap and commercial machines (TAZ 4 on atleast X, Mendelmax 2 on Y axis etc.).

It works well but it does have higher friction than ball bearings, but not so much that it is a problem.

What’s can be a problem though is alignment.
Bushings in general are much more sensitive to alignment than ball bearings, even the slighest misalignment will result in a lot of friction.

To get good alignment you can:

  1. Don’t use more bushings than you really need, as adding more compounds on the alignment problem, and you end up with “stacked tolerances”. E.g I use 3 bushings instead of 4 where possible on both X and Y in my mendelmax-style printer.
  2. Fasten the bushings in some way that has a slight alignment possibility, nylon zip ties actually work rather well, better than e.g printed clamps.
  3. If part is printed in ABS, use aceton to soften such that the bushing becomes aligned when the ABS becomes solid again.
  4. Use self-aligning versions of bushings.
  5. Run “burn-in”

I currently use the IGUS RJ4JP, which are intended as drop in replacements for LM8UU (they are sized correctly both ID and OD).
I can really recommend IGUS + TMC2100 stepper drivers if you want an amazingly quiet machine.
At the moment I’m working on reducing fan noise as my motors and the mechanics make very little noise.

noise reduction is primarily what I’m after but I read reviews for TAZ 4 and also observed the sounds it make from youtube video and TAZ 4 is not a quite machine… anyone has video link showing how quite these linear bearing is? I’d like to hear that. thx

There are examples on youtube, even some direct comparisons between ball bearings and RJ4JP.

@Step_Cia you will likely have more noise from your steppers and drivers than the bearings. But I agree with everything @Oystein_Krog ​ said. He hit the nail on the head. I used the pbc linear versions which work on a similar principal. They are OK, but for the cost I feel that linear bearings are a better option. If you are looking into items in this price range I would consider ground linear guides as a better option.

Way too expensive… $20-30 a piece aren’t they? Why bother? Decent linear bearings are super cheap… $1-$2 retail

I paid EUR 2.7/bushing for the RJ4JP, and that was in packs of 4 from ebay, you could probably get them cheaper.
It’s worth it if you keep your printer very close, I have mine in my living room.

Thanks will look into igus stepper motor.

@Brook_Drumm At retail that Igus part is about US$9. They have another that’s about US$4 that’s quite good as well that I use in some kits. You can get usable LM8UUs for a buck or so retail, under a quarter in bulk. To get quality LM8UU that are speced to a tolerance at retail they’re US$6-10 each. Typically those come from Japan or Europe.

That’s better than I thought! My mistake. $4 ain’t bad

I tried PBC Linear simplicity bearing which is a competitor to this Igus bearing.

I experienced binding issues on one axis, the axis that had the widest spacing. On my X carriage it was fine.

My 300$ lesson was that, those plastic bearing have 0 forgiveness. Even if I had compensated bearing (a little more spacing) so I had leaders and follower bearings, I always had binding.

My 12mm shafts came from china, and were not 100% true, and it was probably the main reason why I had binding. Switching back to lm12uu in my blocks removed the binding all together, as they have more play with them.

Interesting thought and input. Thanks all who chimed in.

@Jean-Francois_Talbot Were your 12mm shafts correctly sized for the bearings?
Please be aware that there are different standards/types of fit, some are always slightly under Xmm, and some are always slightly over (g6, h6 etc ISO type fit).
China shafts are often not specified, I’ve had single orders arrive with mixed sizes/types, making it quite hard to use in a single machine.

If one wants to spend a bit, just get proper linear slides, that way the tolerances are absolutely correct.
Last time I checked RS-Components the IGUS linear slides were in the neighborhood of that price, AFAIK that is what several mendelmax types use on the Y axis.

My H-bot style printer is very noisy. I have always wanted to try IGUS DryLin but I’m also afraid of binding problems.

I’ve tried bronze bushings but they binded like crazy, even though they were nice and snug on the shafts. I suspect that it’s the Hbot style setup that doesn’t allow this due to torquing on the gantry…

Do you think the IGUS will have the same problem?

@Jos_van_der_Plas ​​​ For an hbot, yes:P I too used those bronze graphite bushings, the binding problem is comparable.