Step motor repair (bearing replace)

In this video, we will see how to cure ill step motors.
Worn bearings on cheap Nema 17, are a common issue in 3D printers.
Belt tensioning on one hand, and violent direction changes on the other, are lethal on the long term.
You can change your worn bearings with new 625ZZ, and breathe new life to your old motors.

[@MarkMichalowski]

Matey, this is exactly, perfectly what I was looking for. I didn't even know the bearings COULD wear out! Thanks so much :)

[@SteliosLiver]

Greetings Mark Michalowski, and thanks for your kind comment :-)

[@johanneslode2006]

Great demonstration, thanks. Keep the maker motto up: if you can repair it - then you own it!

[@SteliosLiver]

Greetings Johannes Lode, So true... Works the other way around too... If you can't repair it, you don't own it . Nevertheless, thanks for your kind comment :-)

[@tahsinbatur7035]

Thank you so much. I opened the inside of the stepper motor and I was wondering "what could be wrong with this".

[@SteliosLiver]

Greetings tahsinbatur7035, Thanks for your kind comment.

[@divinecouple1279]

Thanks for posting this video, exactly what I needed 🤓

[@SteliosLiver]

Greetings divinecouple1279, Glad it was helpful

[@joetkeshub]

Helpful. Thank you so much.

[@SteliosLiver]

Greetings Philibert Bon and thanks for your kind comment :-)

[@marklimbrick]

The rotor is instantly demagnetized if removed from stator! 2/3rds at least lost. I found this video searching for a clip in the factory showing how they are magnetized after assembly. It takes a very large current from a special power supply. Be curious and Google before dismantling.

[@SteliosLiver]

Greetings, marklimbrick, and thanks for your comment. The repaired nema 17 you see in this video, is still in use, in a heavily used, large coreXY printer, 2 years after the repair. **And it's not the first stepper I have repaired nor the oldest**

[@aurenosetecnicotajimadahao7247]

When disassemble, it loss at least 20 percent of power. If your use isn't intense or near limits, no problem.

[@douglarue8485]

have all of the motor bearings just pulled off with your fingers? This K40 motor bearing does not seem to want to come off the shaft.

[@SteliosLiver]

Greetings Doug LaRue, The bearings/shaft should have a tight tolerance. Both of my bearings were worn off, therefore they were loose. Moreover a 5mm bore bearing on specs, my not have an actual 5mm bore (many cheap Chinese bearing, don't). Therefore, the bearing might hold on to the shaft too tight, or not at all. In case of very tight tolerance between a worn bearing and the shaft, you could use some WD40 and a small two jaw Bearing Puller/Remover.

[@douglarue8485]

@@SteliosLiver thanks for the reply and it gave me the confidence that I would be able to get this bearing off. I ended up freezing the motor, made a 5.xmm slot in a piece of angle iron and with a propane torch heated the pulley and knocked the motor/shaft out. The inside bearing was loose like in your video but a made a larger notch for the other bearing and, with no heat, a slight tap of the shaft freed the bearing. Now just waiting on the replacement 625zz bearings. You helped save a motor from the scrap box. Thank you!

[@jacob8266]

I feel like I should play this background music while performing maintenance on my stepper motors, it will surely decrease the chances of things going wrong :D On a serious note, I am a few months new to 3D printing and have some serious uneven layers, when I move the belt tensioned steppers by hand, I feel a "tug" that is consistent about every 50-100 mms, (haven't measured yet.) I've performed every bit of maintenance I can think of, as well as check everything I can think of on the software end and it's just not correcting. I wonder if this could be the stepper motor bearings going bad under too much load. Thanks for the video, hopefully this is what is causing the issues on my Ender 3 V2.

[@SteliosLiver]

Greetings futuremind, Remove the belts and move the print head around. Is the movement smooth? If no then check the kinematics. If yes, then start the music and repair your motor. Nevertheless thanks for kind comment and good luck. :-) ps: belts should not be too tight (or loose, but that's not your case)

[@dougbraun4905]

I had the exact same problem - it was a motor bearing. I took the motor apart, put some oil in the bearing (it was not sealed), and the problem disappeared.

[@asr-st]

solved...

[@SteliosLiver]

Greetings Asari Stone, I like your way of thinking :-) On the other hand, *there are two 625ZZ bearings in there*. One of them was changed a year ago, and since then the motor works as an alpha stepper in one of my coreXY machines... And this is not the only stepper motor that I serviced, the way you see in the video...

[@asr-st]

@@SteliosLiver 325ZZ bearing does not exist, and it's not the one used in nema 17

[@SteliosLiver]

@@asr-st hmmm... The bearings are *625ZZ* as stated @ 1.36 in video. There was a typing error in the video description... I changed it to the correct value... Thanks for your comment :-)

[@asr-st]

@@SteliosLiver nice! that's what I meant about the description ) i'm just rude ) sorry!