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[Solved] Bearings scratching rod after relubricating  

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SaguaroMaster
(@saguaromaster)
Active Member
Bearings scratching rod after relubricating

I purschased an MK3S second hand which has quite some printing time behind itself at 190 days, from a print farm. I did not notice any scratches on the rods, but they seemed dry so I. Before disassembly, when I cleaned the ends of the bearnings from dust and everything I moved the X axis by hand and it left scratch marks. I dont know why could have that happened, maybe its time has just come at the wrong moment? 

After that I disassembled all axes, washed out all bearings with IPA and then relubed them with TOTAL Multis-Complex EP2 as I don't know what lube did the previous owner use, which in theory is something like the Mogul LV 2-EP that is recommended by Prusa here. It is some kind of Lithium complex grease. (Maybe it is not compatible?). I have checked all the bearings by sliding them on the rods (all of them slid down the rods with the lubricant applied from just the force of gravity), all of them worked fine except the one that only moved in one direction, probably that was the one that scratched the rod. During the process watched that no dirt or anything gets into the bearings. After regreasing and assembling everything (I have left out the bad bearing, only used one on the right Z axis rod), I printed a perfect benchy, but on the lower rod of the X axis there were new scratch marks where most of the print moves took place.

I have not noticed any stickyness or anything, so what could have caused it? I have already ordered some new bearing which should come tomorrow, so I will follow up with the results from the new bearings, but in case I did something wrong I wanted to ask it here, maybe someone can correct me.

Also, the bearings on the Z axis run fine and don't scratch the rod, but when disassembled and moving the rods trough them manually, I could feel some not-so-smooth motion, as it's not sticking or anything, its just simply not perfectly smooth, is it normal?

The bearings I bought it with had no markings on the metal so they are probably not Misumi ones and have already been replaced at least once. How often should they even be replaced?

Best Answer by SaguaroMaster:

Ok so i replaced the ones that were scratching the rod, they came prelubricated with white grease. Now it runs fine. I found it important not to overtighten the screws that hold the plastic panel holding the bearing in place on the X axis. I tightened them with the motor off and while moving the extruder up and down by hand. As soon as it starts being louder and harder to move its done.

Posted : 24/05/2022 6:39 pm
cwbullet
(@cwbullet)
RE: Bearings scratching rod after relubricating

 

Posted by: @saguaromaster

I purschased an MK3S second hand which has quite some printing time behind itself at 190 days, from a print farm. I did not notice any scratches on the rods, but they seemed dry so I. Before disassembly, when I cleaned the ends of the bearnings from dust and everything I moved the X axis by hand and it left scratch marks. I dont know why could have that happened, maybe its time has just come at the wrong moment? 

After that I disassembled all axes, washed out all bearings with IPA and then relubed them with TOTAL Multis-Complex EP2 as I don't know what lube did the previous owner use, which in theory is something like the Mogul LV 2-EP that is recommended by Prusa here. It is some kind of Lithium complex grease. (Maybe it is not compatible?). I have checked all the bearings by sliding them on the rods (all of them slid down the rods with the lubricant applied from just the force of gravity), all of them worked fine except the one that only moved in one direction, probably that was the one that scratched the rod. During the process watched that no dirt or anything gets into the bearings. After regreasing and assembling everything (I have left out the bad bearing, only used one on the right Z axis rod), I printed a perfect benchy, but on the lower rod of the X axis there were new scratch marks where most of the print moves took place.

I have not noticed any stickyness or anything, so what could have caused it? I have already ordered some new bearing which should come tomorrow, so I will follow up with the results from the new bearings, but in case I did something wrong I wanted to ask it here, maybe someone can correct me.

Also, the bearings on the Z axis run fine and don't scratch the rod, but when disassembled and moving the rods trough them manually, I could feel some not-so-smooth motion, as it's not sticking or anything, its just simply not perfectly smooth, is it normal?

The bearings I bought it with had no markings on the metal so they are probably not Misumi ones and have already been replaced at least once. How often should they even be replaced?

I replaced mine after 6 months with Misumi.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 27/05/2022 10:24 am
cwbullet
(@cwbullet)
RE: Bearings scratching rod after relubricating

 

Posted by: @saguaromaster

I purschased an MK3S second hand which has quite some printing time behind itself at 190 days, from a print farm. I did not notice any scratches on the rods, but they seemed dry so I. Before disassembly, when I cleaned the ends of the bearnings from dust and everything I moved the X axis by hand and it left scratch marks. I dont know why could have that happened, maybe its time has just come at the wrong moment? 

After that I disassembled all axes, washed out all bearings with IPA and then relubed them with TOTAL Multis-Complex EP2 as I don't know what lube did the previous owner use, which in theory is something like the Mogul LV 2-EP that is recommended by Prusa here. It is some kind of Lithium complex grease. (Maybe it is not compatible?). I have checked all the bearings by sliding them on the rods (all of them slid down the rods with the lubricant applied from just the force of gravity), all of them worked fine except the one that only moved in one direction, probably that was the one that scratched the rod. During the process watched that no dirt or anything gets into the bearings. After regreasing and assembling everything (I have left out the bad bearing, only used one on the right Z axis rod), I printed a perfect benchy, but on the lower rod of the X axis there were new scratch marks where most of the print moves took place.

I have not noticed any stickyness or anything, so what could have caused it? I have already ordered some new bearing which should come tomorrow, so I will follow up with the results from the new bearings, but in case I did something wrong I wanted to ask it here, maybe someone can correct me.

Also, the bearings on the Z axis run fine and don't scratch the rod, but when disassembled and moving the rods trough them manually, I could feel some not-so-smooth motion, as it's not sticking or anything, its just simply not perfectly smooth, is it normal?

The bearings I bought it with had no markings on the metal so they are probably not Misumi ones and have already been replaced at least once. How often should they even be replaced?

I replaced mine after 6 months with Misumi.  Mine did not scratch the rods, but they were making an evil hum.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 27/05/2022 10:25 am
SaguaroMaster
(@saguaromaster)
Active Member
Topic starter answered:
RE: Bearings scratching rod after relubricating

Ok so i replaced the ones that were scratching the rod, they came prelubricated with white grease. Now it runs fine. I found it important not to overtighten the screws that hold the plastic panel holding the bearing in place on the X axis. I tightened them with the motor off and while moving the extruder up and down by hand. As soon as it starts being louder and harder to move its done.

Posted : 27/05/2022 11:03 am
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