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Motor cans keep coming loose WAHHH

I have a couple of TB 6355 190kv’s and the screws securing the cans to the shaft keep coming loose. Happens on both sides, if it’s not one coming loose it’s the other, constantly. I’ve tried everything I can think of - replacing M4’s with longer 12.9 alloy socketheads; M4 grubs; blue, green (290 and 609 retaining compound), and red threadlock, all on different occasions with different fasteners (always waiting 24 hours to cure). IDK how the red threadlock comes loose other than motors heating up (although I always feel them and they really aren’t getting that hot). IDK what to do guys but these motors are almost toast from just trying to secure these cans over and over. I’ve tapped the threads once already because I stripped them and it’s still happening. HELP?

You need risers

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goddamnit. hahahah

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Lol.
Naw.
So what tools you using ?
How much loctite? Too much will make it take longer. Almost everyone uses too much.

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Mine started doing that after 1000+ miles or so. Replacing the set screws with m4 machine screws fixed it for a while until the heads popped off somehow…

Sounds like you’ve already tried that… Wish I could give more insight, I’ll wait to see if anyone else knows a solution.

On mine, there looks like there’s a slot in the shaft for one of those rings to keep things in place… Maybe mine not having that or maybe me not putting it back on properly is what caused this. My cans would slide down towards the end of the shaft.

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ahhhh hmm yeah prolly too much. I started with just a drop and then since it didn’t do it I cover the whole thing with it…Ehhh. If I do that and wait 3 days you think it’ll be ok or will too much inevitably come loose?

If I’m adding Loctite to a bunch of different stuff what I normally do is put a little pool of it on a business card or something and then just roll each bolt through it lightly

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hmmm well shiiiat. Maybe I’m just using too much and not waiting long enough because I cover the bastards in the stuff now. Will have to dial it back

It’s a super common thing.
Everyone seems to use too much.

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Another possibility: Have you been cleaning the holes and screws before reapplying? Dirty surfaces make threadlocker not work.

Also, it’s possible that your issue isn’t with your screws - you may have some deeper underlying mechanical issue (vibration, resonance, impacts, etc) that is causing undue stress on the screws that they just can’t take, even when you have properly tightened and secured them with loctite.

How loose is the motor shaft in the can when the screws aren’t tightened down? It should still be at the very least a snug sliding fit with no play or wobble, or better yet a press/interference fit.
The majority of the strength of this joint comes from the fit of the shaft in the can, not from the screws - the screws are there solely to keep the shaft from spinning or moving laterally, not to support the weight of the can.

If your can is not a good fit on the shaft, then you need a new can and/or new shaft. Therre’s no way around that.

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Yeah just a touch / drop is enough, and drying for long enough. I used too much on my first build when I installed my mounts and opposite of whaddys issue it glued the screws in, resulting in having to use a blowtorch to get them out lol

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Hmm, yeah so I also set retaining compound around the shaft where it meets the can but when the screws come loose, the shaft inches itself out of the can (only by fractions of a mm) but it’s significant enough that the motors start making that sloshy sound when throttling and braking, and the braking and accelerating ability also is cut almost in half.

edit:
I also have not consistently been cleaning the holes out before reapplying threadlock. Half the time I do with alcohol very thuroughly and the other half I’m just fuck it and throw more in =/

Sounds like you need a fresh set of cans my dude. Sorry.

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I know. TB sent me one but the hole for the shaft was smaller than the ones on the versions of their motors that I have - waiting to hear back from them about that =/

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make sure to clean everything as thoroughly as possible with isopropyl alcohol before adding the loctite. I used 638 and let it cure for 72 hours for full strength. shaft hasn’t moved since.

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@b264 I know I know, I wish I could do something like this but I don’t have those kinds of tools man

20190716_201122

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Is there any acceptable approach to this for someone who’s only got a drill gun and a dremel?

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