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Discussion in 'Electronics' started by Josh Lambeth, Dec 18, 2012.
Yes they are...
Well I think I am going to get another set and send these back to them... Should I do this or just order the EZO replacements?
What has happened since this last update?
I also am frustrated with replacing bearings and then having more shaft movement than before replacement.
I waited for a full month for Canadapost to finally find my bearings in customs and deliver today (another frustrating story all of its own). I have Bart's tool and installed two replacement bearings in my qc3328 motor that had less than 20 flights and sounded terrible before replacement. I ordered the Boca set for QC motor, the Abec 5 ceramic. SMR694C-YZZ #5. After replacement, the motor has terrible shaft movement side to side. Not flown it yet as we have 'Hawaiian Express' rainfalls right now. I suspect something is wrong with tolerances claimed by Boca bearings. Placing new Boca bearing on new spare motor shaft I find more movement that doing the same with old bearings just removed.
I think I should return all 10 sets of expensive bearings to Boca and just purchase the cheaper tiger replacements.
What have you found to be the solution?
I've seen others saying that you should get ABEC #7 as they are the better quality, but I can't attest to that from personal experience.
Yes was going to try those#7s, but I thought I would try #5 as they should be adequate for purpose.
Guess not perhaps, I sure did not expect to have more play now.
Having to replace bearings after less than 20 flights on brand new motors, with no tree or ground incidents, and spend $30 on bearings on top of already expensive QC motors, seems crazy. I have had better luck with HK motors bearings (although more vibrations and don't seem as efficient).
I have 10 sets of #5 Boca bearings I am thinking of returning now....
I see Josh used the #7 (ok different bearings for 3515s) but he had same problem.
So just wonder what his solution has been....
We haven't had a choice but to fly on these bearings. So far they still have the play in them but it doesn't seem to get any worse. Brad did mention to me that he thinks maybe I need to adjust the shaft length by loosening the two hex screws to help hold everything together better and it should eliminate the extra play. I haven't had a chance to try that yet. I will try that sometime soon and if that doesn't work I will be ordering new "STOCK" bearings from someone and return these Bocas. Really is a shame because it's not a short process to replace them all!
Sean... make sure the motor shaft is not moving vertically after the bearings are installed. I just got my Boca's and the ones i replaced all needed the shaft adjusted to stop vertical movement. For me after snugging up the shaft ( just enough as to not pinch the bearings ) there was no movement vertically and no side play has come into play either after 10 flights.
I think the depth tolerances are off on the boca's and if you have vertical play you eventually will get horizontal, in particular with big loads.
I will update how they look after 20 flights.
I was thinking of adding an entry to the FAQ regarding tightening up the motor bearings, but I've been searching the forum to find out how people are doing that. Brad: could you give a detailed description of you do "snugging up the shaft," please.
Yup sure thing... I'll post something this afternoon with nice pictures
So I have to ask. If the issue is side to side play, i.e. the inner bearing race is not snug on the shaft, how would adjusting the vertical sliding of the shaft fix that?
If you getting loose side to side right after you put them in then you have issues beyond what I am saying.
To sum up what I saw with two sets I just replaced in 3515's is the top bell with the magnets attaches to the shaft with usually two hex screws. The height or depth of the boca bearing replacements is smaller which after you re-attach the clip and washer to the shaft allows for slight vertical movement. This if unfixed will lead to side to side play after a few flights due to the forces on the shaft and bearings from the propeller. You need to loosen the hex screws and push the shaft further into the bell and re tighten so that there is no up and down play.
I have no side to side play with the #7's I got and thru 10 flights so far, no vertical play either. So maybe with other sizes there are other issues but I don't know.
btw I am almost out of replacement clips which are different and don't work as well. I haven't found the exact ones that come with the MT 5mm shaft. Anybody found the exact replacements?
I believe these are them: http://www.amazon.com/gp/product/B0062OEFNQ/ref=oh_details_o03_s00_i00
McMaster Carr 98541A113 $5 for 100 I think you need the 5mm, shaft is 5mm on the 3515? The 4mm of these is the same as Bart includes in his install kits.
Thanks to Brad's suggestion regarding the need to adjust for the vertical play, I did the same on the QC3328 motor.
In doing so tonight, I decided to remove and inspect the motor shaft while I was at it... It seemed to vary in diameter such that the old stock bearings would not slide up the shaft... Got stuck half way... Shaft not bent, just had variance in diameter along it. After installing new shaft and putting it all back into one piece, I adjusted the vertical play.
Wow, what a difference. Removed just enough play in vertical shaft and seems fine now. In fact, the motor with bearings replaced really sounds and feels now much smoother than the stock bearing motors. At least on bench. Need to test fly it, and see real result over a few flights, but it sure is a much more positive a result than last night. Thanks Brad. You are da man!
Im not sure what I am doing wrong... but I am loosening the 2 set screws on the motors to loosen the shaft from the bell but I can't get the shaft to budge! Any ideas on how to do this correctly?
Same issue here Josh. Looks almost like the shaft is glued from inside the bell.
What did you end up doing?
The shafts are a press fit. If you are going to be pressing them you will need heat and a press. A little up and down endplay is not the end of the world. Personally my motors all have a tick of endplay and work fine. If you start pressing them 100% tight you can easily damage the bearings.
If you are going to adjust just go slow and be careful or you will be buying lots of bearings!
.. Became frustrated, mounted a spare motor.
You gotta take the Bell off and tap the shaft and it will move. Probably it is loctited in place and some heat might help.
I do it after I get the bearings, washer and clips on so it pushes the play out. Just be careful not to hit it too hard and damage the bearings.
These ones (Boca) need to be done or they will go off fast. I verified that now by leaving one of them with vertical play. Yes go slow.