I seem to remember a discussion about the need to oil the motor bearings every 6th flight.
I was on the phone with 3DR about another subject and when finished I said "oh by the way"
blah, blah, need to Lube? and the answer was yes, I will send you the directions.
I did not receive the information as of 2 weeks later.
How often to do oil the bearings?
with what oil?
Decades ago I built anemometers for a research project and calibrated them in a wind tunnel. I found that
it was better to run the bearings dry as it did not collect dirt as well. The bearings were very lightly loaded
so it seemed to work. It seems to me that when I fly and apply vigorous attitude adjustments the bearings are sufficiently loaded to require Lubrication.
Can I get a witness?
How about, how often and the technique.
If the stuff on the bottom is removed with liquid....
it is not magnetic because it would stick and be difficult to get off....
Do you agree?
I saw the magnets...are the bearings are covered with the same colored stuff?
Not only liquid (alcohol or contacmatic I used a wood toothpick and a clean ear to help remove the stuff it's give me some work; it was like a dirty heavy grease, that let me think that bearings loose grease but I didn't have or find quickly new ones so I decide to try this and they are working yet :) (aprox tree years).
3 years, once per year maintenance.
How often do you fly?
Don't take as a scientific recip, it's only what I do now before aprox two years flying the copter and find that problem when I was curious to see how the motors are inside after a time flying, it's the first post that I read about lubricating the bearings, I noticed them little crispy and decide to do that.
It's variable my flying time, I fly more often in spring and summer monitoring crops and sometimes weekends, perhaps two hours a week in average aprox but I don't have stadistics. Perhaps it's a good work to do in winter when cool weathers come and flying times are less, I'm in summer now, I'm going to re-check them this winter, perhaps it's a good practice too to put a little drop more often but I don't shure how that practice works with dust, oil outside the bearings go to magnets I think and helps soil to stick to them and give another problems (imbalance, etc.) any experiences with this practice?.
way In the past I took care of weather stations on farms in Hawaii. The soil would become
airborne during the dry months and the wind speed an direction instruments were mechanical
and had ball bearings. During testing the ball bearing had heavy grease as delivered by the factory.
So I cleaned the bearings and ran them dry to prevent soil trapped by grease.
For a copter, the load is mainly thrust..an axial load ..up and down, and the bearings were designed for radial...side to side load.
My feeling now is to avoid crunchy feeling of rotations by hand and replace ...bearings and motors before they fail because it is more expensive to replace a drone than motor.
That said, your cleaning has resulted in you still flying in dusty conditions..and I congratulate you
for your work, thanks for sharing.
Do you use a color or B&W camera with deep red...NIR filter?
Yes Dan, I think like you, this year I'm going to replace my motors, first I think to replace bearings but good ones were more expensive than my cheap motors and I didn't find that size in my country so I decided to change and update my motors for a more efficient ones this year but I learn that if I do little maintance and control, I can fly safer longer time and prevent crashes, I'm shure that, if I not checked that, a motor fails and crash, I was luck; sharing my experience, perhaps I animate others to look their motors, pilots near me is rare that they dis-assemble them only to check. Thank's to share your experience.
I thinks that the grease that I found outside tells me that my bearings have days numbered.
I use RGB (color) and NIR (B&W)
That's some interesting stuff, but it isn't really made for ball bearings and might not have the film strength you need.
This is Super Lube and it is definitely made for small high speed bearing use:
It is also available in a tiny injector bottle but is way more expensive and I prefer to buy it as a light grease:
And put it on with a toothpick (I also use it in the linear ball bearings and ball screws of my CNC machine).
I also think that the heavier body of the grease helps it stay intact on the bearings longer.
Top quality skateboard or inline skate lubricants should work well also.
But you definitely want a top quality synthetic and with additives like PTFE and that lube you are using is organic and none of those.
I think the chain lubricant you are using may actually be causing some of your problems.
Because they need to stick on the chain and not wash off in rain and puddles, chain lubricants tend to be very tacky and actually pick up grit.
They generally contain a solvent which thins the grease when you put it on, but then which evaporates leaving a sticky film.
(I am enclosing a link to the PDF that points out it is solvent based and is designed for gears and chains (not bearings)).
(Looking at your old motor photos, this could be part of the reason for the grit buildup).
(Which is why they tell you to periodically immersion clean your chain and reapply the chain lube).
This is not what you need for tiny ball bearings.
This Super Lube grease will work much better and will not attract dust and grit.
It is a full synthetic grease with PTFE additive and is excellent for these applications, it will also not build up into a stick mess like chain lube.
You can also get it in a thinner oil, but I prefer the light grease which I can put on with a toothpick.
I know you may have trouble getting super lube, but I greatly recommend a light synthetic light bearing lubricant with PTFE additive.
MOS2 (Molybdenum Disulphide) might be OK alternatively).
But in any case, definitely not a solvent containing sticky chain lubricant.
Thank's Gary, really what cause my problem are the cheap motors, that dust was from original grease, I didn't open again before clean them but Im going to try to find your recomended grease, I think that I can find here with that specifications, my only doubt if it a good bearing with a well seal, grease can penetrate it? thank's for this discussion, very interesting to have someone else to change ideas.
Hi Cala, sealed bearings are a different matter, most of the ones we use aren't.
Sealed ones are generally not designed to be relubricated at all and are very hard if not impossible to do so (dip solvent base type).
Some with plastic seals can have lubricant injected into them, but ones with stainless steel wipers can usually not be relubricated at all.
You throw them out when they go bad.
So really it not have sense to relubricate owr bearings? better to have a reposition stock and change when they go bad or change after X hours of flying time to avoid crashes? what do you think is better?