Top bearings on X-Carriage chatter  

Active Member

Hi Everyone,

I'm a new member of the Prusa family.  Bought the MK3S+ kit and had a grand time putting everything together.  Machine makes awesome prints.  I've normally been printing in the center of the bed.  Just today I printed something in one of the corners and I noticed some bearing chatter during a print.  I printed again in the middle of the bed and the chattering wasn't as pronounced but quite present.

I've narrowed the problem to the top two bearings on the x-axis carriage.  The top rod on the X-axis vibrates when the carriage moves across it.  The bottom rod is smooth and quiet.

Any ideas on how to fix the chatter?

I was thinking to open the back of the carriage, cut the zip ties off the bearings and slide them around to see if one is the culprit.  Maybe a stuck or loose ball inside?  Any issues with the rod to for?  Belt tension is within specified parameters.

Any insight would be helpful.  Thanks/Livius


Posted : 03/04/2021 8:41 am
Dan Rogers
Prominent Member

It could mean that the two bars are not fully seated.  Check the inspection holes at each end for both bars.  Either one out of alignment can make things move jerkey.  There are two holes where the end of the holes for the X rods (horizontal rods) would bottom out - these are inspection holes to let you see if you fully seated both rods.


Posted : 03/04/2021 4:00 pm
Active Member


Thanks for the direction Dan.  While the rods looked seated, I took a straight edge to the top side and found the top rod a little bowed, sagged in the middle.  I actually pushed out the top end of the idler and x-axis motor mounts and got a "snap" reset on the fit.  I even wrapped the rods with chip board and with some good channel locks spun the rods in place to free any additional stress.  Sounds much better now.


Posted : 04/04/2021 1:00 am

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