IGUS version of X-Carriage for Prusa i3 MK2S

by Tareko Mar 27, 2017
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I use metal IGUS ones that are exactly 1 mm bigger for both diameter and length as well (they are basically RJ4JP-01-08 with metal cover), I redesigned my x-carriage but have hard time converting SCAD files to usable Inventor (IPT) ones.

Can you share your model's files by chance ? Even if they are SCAD ones, the hardest part is already done for what I can see...

could you please tell me the distance (center to center) of the x rods? thanks

It would be awesome to have a version that is using screws to hold the bearings instead of using the zipties. That would be a huge improvement to me.

That's outside the scope of this thing.

I have the RJ4JP-01-08. These bushings are slightly smaller than a typical linear bearing. They are also suppose to be compression fit into a housing. How does this design compress the bushings? Shouldn't a cap over the bushing be necessary?

The RJ4JP-01-08 do not require the press fit.
"Quickly installed, secured by circlips"

The RJM-01-08 do.

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

That's interesting because when I swapped my linear bearings for the RJ4JP-01-08, they rattled inside the pillow blocks. I found the bushings were slightly smaller than the bearings and wouldn't fit snug. I believe it was Tom's youtube video on the igus bushings that said they should be under compression.

As you see - this information comes from the manufacturer. These bushings are not snug, otherwise they wouldn't move and yes - they are loose (as per specs - their tollerance is 0.04mm, which is quite a lot). Also, are you sure that your shafts are perfectly made?
I think it was on Prusa3D forum - I saw a post, where someone says, he got the information confirmed by Igus guys - that RJ4P are designed to be used wthout the compression and the RJM to be press fit.I did replace my ball bearings with MJ4JP only to realise, that I can live with the noise if it has less play on the shafts, so... the ball bearings are back in the machine.

Ah. I may have made a mistake in the exact sizing of that part. If you try it, let me know if it ends up too big. I didn't realize I hadn't uploaded the OpenSCAD files, so I'll do that shortly. You can then simply edit the bearing.scad file.

Sounds good, thanks!

Why does the X-Carriage need to be changed for Igus bushings - I thought they were drop in replacements? I'm considering moving to Igus, so would be interested to know if I'll need this.

Not all of them are, hence the change. Some are direct drop-ins, but some are slightly larger, hence necessitating the file.

Hi there,

nice to see someone modify the carriage for the Igus bearings!

But what are the differences compared to the stock version?

You should look at the specs yourself, but in a nutshell: they are bushings, not bearings (no balls, moving parts). They fit the rod tighter, and they......run smoother. Quieter too.

plz tell me were are the difference ?

Differences are that those bearings have a diameter of 15.0 mm and a length of 25.0 mm while bearing provided with your prusa are 1 mm less for both diameter and length. Direct consequence when you try to use them is that they don't fir with x-carriage and if you try to "force" them in position, your X axis will use additional force at the edges, since bars aren't perfectly parallel.

try a diff to the original. Should be pretty straight forward.