Replacing Ball Bearings in Chinese MGN12H Linear Rail for 3D Printer
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- Опубликовано: 6 апр 2018
- This video shows the differences in motion before and after replacing ball bearings in chinese MGN12H linear rail for my Tevo Tarantula 3D printer.
I have 3 sets of rails
1 will be for my Y axis and the other 2 for my Z axis.
Here is a link to the ball bearings:
100 3/32" Inch Chrome Steel Bearing Balls G25 www.amazon.com/dp/B015RKOZ7G/... 
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I ended up using ceramic bearings. This worked great as I was having a lot of shifting and finally figured out it was the bearings. Thanks for the video.
CLTaggart if you don’t mind, post a link to where you got your ceramic bearings for anyone else interested. I have been wanting to try it with ceramic bearings too
Here are the bearings I used. Make sure you get enough as I thought 100 would be plenty and each side of the rail cartridge has around 37 bearings.
3/32" Inch Si3N4 Silicon Nitride Ceramic Ball Bearings G5-100 Balls www.amazon.com/dp/B01AXDD2JE/ref=cm_sw_r_cp_apip_oYK7y1vfGHH9X
wanted to chime in here. I watched a bunch of other videos, bought suggested grease, took apart and cleaned them as suggested, nothing worked. I ordered the bearings you suggested and they improved as you showed, instantly. the rails wouldn't move even if I held them vertically and flicked the carriage. after replacing the bearings it moves with slightly elevating one side or the other. thanks so much.
Sam Antics I’m so glad that it worked out for you. Milling the rails and the inner metal flat is the easy part of manufacturing these for the companies. Ball Bearings are precision items that take time and know how to manufacture properly.
To be fair the measurements came from a forum post I had read about these
I gambled and wanted to share the result.
I’m so glad it helped
Hey thanks for this video! I'm actually in the process of designing a new printer from scratch using the same size Chinese rails. I'm about to order the parts for it soon, so I guess I'll be picking up some new bearing balls too :)
Ronald Finger Thanks !
Hey, if your up for an experiment. I learned after the fact that Ceramic Ball bearings are supposed to be even smoother and believe it or not, handle a higher weight load than steel.
I used Chromed steel bearings. But if I can do it again would be interested in trying ceramic oo
can't believe I stumbled upon Ronald!! love the fiero series
Thanks a lot !! I have the same problem and was about to order new MGN12H
Thanks for the info. I ran into the same problem with mine. Did you end up applying any grease? Would you recommend it?
Matt McArthur I have applied the grease on the y axis
I must admit that it was extremely difficult to get the rail back on without the ball bearings sticking and wanting to come out with the grease
I haven’t noticed friction problems without the grease on my x axis yet.
My advise is to get the carriage on and Apple a small amount of white Lithium Grease to the rails where the balls contact the rail and work it back and forth the full length of the rail. Use your finger to wipe off remaining blobs.
Awesome video. If you could do one of the process of swapping them and loading them up with grease that'd be great.
EDIT: Which version of the mgn12 did you order?
Derek S I have more bearings and the rails for my Z axis coming in another month or less.
I will do my best to do a video !
I should mention, after packing one with white lithium grease, I’m not sure I would do it again. It made the balls sticky-ish and made them want to come out as you put the rails on. I’ll need to do some reading first
Good to know. Where did you order these?
Derek S the linear rails were from eBay. I just searched for MGN12 rails in North America. I then picked my length and voila !
For the bearings I believe they are BG bearings from Amazon
WaldvogelReview sweet. They're pretty cheap on eBay so that's where I was hoping you'd say.
Thanks for your idea!! How many balls are in mgn12h?
What is your opinion about Silicon Nitride Ceramic Bearing Balls? Or Zirconia Oxide?
I haven’t counted the ball bearings honestly
It’s just a feel thing, you know when the gap is too big or too small for another
As for the alternative types, I haven’t tried anything other than chromed steel
I was entertaining the idea of Ceramic, but haven’t tried them yet
so you had to buy 2 sets for those 2 rails?
davidtriune I believe so yes. There will be extra ball bearings afterwards too
I keep em as spares
Thanks for this video, it inspired me to go spend a tenner on a bag of simply bearings grade 100 balls and some WD40 white lithium grease....
Unfortunately it made very little difference. Note, my MGN12H clones contained 33 balls on either side, 66 total!, wish I'd bought a bag of 500 to do all my 6 blocks!.....
Of 6 MGN12H blocks purchased total, 3 are pretty good and 3 are very sticky, BUT, 1 of those 3 seems to move very well under load. I'll have to run some more tests. maybe there's a pre-load version shipped in error?
During my research for MGN style rails, Fred BST automation keeps coming up. I purchased mine from Hong Yi, who's been mentioned in a few forums, and who's service is fantastic, we're having a dialogue now about possible ways to getting the blocks running better!.
For the ££, (about £95 / $125 all up for 3 x 500mm rails and 6 carriages) , I'm happy i've gotten three great working rails and carriages. Lesson I guess is if it's a quick project, spend more ££, either by getting the supplier to test / guarantee before shipping, or just buy a couple of extra carriages and hope for the best
I should mention that I put White lithium grease on one set, and I felt it actually limited the smoothness and increased the amount of energy needed to move the carriage. Will it last longer in the grand scheme of things? I honestly do not know. I am not a authority on bearings or linear rail at all. I simply got a wild hair up my butt to give it a try for a tenner, just like you. It worked ! So for my other 4-5 sets I have not added grease. I put 1 drop of that drill tap\cutting oil stuff on either side on a couple. I do not know if it actually made a difference in the long run.
I will say my video that shows the carriage movement without grease\oil on some chromed bearings from a actual bearing manufacturer is a consistent improvement on every set that I have done.
What size where the original balls?
Swaney Cool it’s in the description 3/32
They just don’t have the same precision tolerances from factory as the replacement ball bearings
It could also slide easier if the ball bearings are even probably just some microns smaller, couldn't it? Could you see if the new vs. original bearings allowed the carriage to wiggle more?
perspectivex absolutely not
I did a test trying to create some flex or movement and they are rock solid
Still equally as hard to get onto the rail without losing bearings (unless you have a plastic transition piece)
I have not noticed any problems
When using 2 for my z
The smallest offset between the parallelism of the 2 rails still will cause binding on the x gantry
They seem to have plenty of precision to me
Also measuring the chinese ball bearing you can get discrepancies between them
cool, thanks for the clarification.
I did this because i was having issues to, i found that actually the rubber ends (that pick up the dust) are causing a lof of friction. When they are not on the blokcs the blocks go really smooth. Any idea how i can counter this?
The Gov I can’t really “recommend” anything without seeing the problem. What you might find in the races and toward the ends is burs or small catches from machining that prevent your bearings from doing the turnaround smoothly. It could also be that the plastic/rubbery ends are poorly made and doing that same thing. Either way, something is in the way of the ball bearings recirculating in the oval-like raceway they follow.
@@waldvogelreview7755 Thx for your reply. I removed the rubber ends en replaced them by 3d printed ones. these do no catch dust but now the rails move super smooth.
@@ISFRedSandman Maybe if you printed them in TPU ? LOL
@@waldvogelreview7755 Lol, i have soms TPU laying around, i could modify the model a bit so it does touch the rail slightly xd.
@@ISFRedSandman In case youre wondering, I did not use white lithium grease after testing. I cleaned it again and have been using SuperLube brand silcone\PTFE lubricant
Once opened, the accuracy remains the same?
Tácio Lopes yes there is nothing sensitive about the assembly
How many spheres will go in each 15mm block?
I have no idea what you mean
35 to 40 if not a little bit more
sold me at....it just flew right off