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Uranium

pinion gear came loose

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another pointless thread?

hey y'all. i told you i never ran out of questions. i was out for a night drive with my tt02. after a bit it made an awful noise and i stopped the run early. first thought the esc went bad, then i thought the spur and pinion went to the dentist and had its teeth pulled out. when i went to look the pinion had came loose since the screw (?) holding it in untightened itself.

i think this was my 12th run while owning the car and this never happened before. is it normal for the pinion to come loose like that or is that my own incompetence? be honest...i'm running 22t pinion, the stock torque tuned 540 motor with the tble-02s ESC if that's important.

edit: i realized the title said spur instead of pinion. guess i am a bit dumb, hah.

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I'd say the more questions you have, the smarter you are.  Because if you are absolutely sure about everything, you could cling onto funny ideas (like the earth being flat or we all live in the Matrix which could be fun, but probably not true).  

Anyway, I don't think it's normal for the pinion to come loose after 12 runs.  [1] Did you use lock-tight?  If you don't have it, even a drop of school glue might be better than nothing.  [2] Did you line up the grub screw with the cut facet of the motor shaft?  You'd think it'd just line up, but surprisingly, the grub screw can bite onto the surface at different angles like 5-15 degrees.  In such case, it could come loose.  

eZaghZV.jpg

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1 hour ago, Juggular said:

I'd say the more questions you have, the smarter you are.

i hope so, cause i'll have a lot of them...

1 hour ago, Juggular said:

I[1] Did you use lock-tight?  If you don't have it, even a drop of school glue might be better than nothing.  [2] Did you line up the grub screw with the cut facet of the motor shaft? 

1. no, as i don't want it to be impossible to uninstall in the case i ever want to change the pinion. but i guess i'll try some elmers...

2. not on the flat part i don't think, but it's tightened on the flat now. hopefully it'll stay tight without some glue. thank you for the ideas!

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Like Juggular pointed out already I would say you have to check the flat part. Also, I've never used threadlock on pinion grub screws, and I don't remember ever getting a loose pinion.

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6 hours ago, Uranium said:

i hope so, cause i'll have a lot of them...

1. no, as i don't want it to be impossible to uninstall in the case i ever want to change the pinion. but i guess i'll try some elmers...

2. not on the flat part i don't think, but it's tightened on the flat now. hopefully it'll stay tight without some glue. thank you for the ideas!

Loctite Blue allows you to easily take it back off. I had the same issue as you once and have been using it since. A tiny tiny tiny drop is all you need.

http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite-Threadlocker-Blue-242.htm

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As above - threadlock comes in different strengths, usually colour coded. The blue stuff will hold against normal mechnical stresses, but not so strongly that you can't take it off again with the proper tool. Purple threadlock is even gentler, suitable for fine screws and bolts. Red is stronger, for things you are unlikely to ever want to take apart again. 

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Medium Loctite 242 or 243 (same as 242 but with better oil resistance) is what you want to use. Sure if you tighten the grub screw with enough force and the stars align it may not ever come apart even without thread lock, but using thread lock really idiot proofs the process. I've never had a screw back out with blue thread lock on it, even ones that I purposely only did up gently, or completely forgot to re-tighten after adjusting. 

Also put some thread lock on the two screws holding the motor to the motor mount, otherwise they can work themselves loose with heat/vibration too. Really any time you have a metal screw going into a metal threaded hole/nut in RC stuff, thread lock should be used. Where one part is plastic and the other is metal, don't use thread lock. When a plastic-metal threaded connection becomes loose, it's time to replace the plastic part.
You may need to step it up to red (high strength) threadlock to prevent screws loosening where they are subject to high temperatures or a lot of vibration/force. If you even need red thread locked screws out, just run it for a bit and take it apart when it's hot, or apply heat with a soldering iron. The blue (medium) should at least prevent screws backing out completely and being lost in almost all cases. I have purple (low strength) as well, and didn't find it to be useful - small screws still loosen with it over time.

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You can just use a tiny bit of cya glue on the grubscrew, it’ll still come undone easy, but it won’t back out on its own. I prefer it on rc cars to loctite as the glue gets less stuck over time (meaning years). Loctite products often get more stuck the longer they stay done up. Great for 10-25mm bolts, not great on 3mm grub screw. 

The tamiya anerobic gel seems to be ok if it’s not left for a long time before you undo it.

generally speaking though I’ve never used any locking compound on any of the 100+ pinion gears I’ve used and never had one come loose either. 

Juls

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On 2/21/2019 at 7:29 PM, Juggular said:

I'd say the more questions you have

Did you draw that with a mouse? I am having difficulty believing so because the lines look drawn like with a pen, and am curious on what you used. 

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4 hours ago, Kingfisher said:

Did you draw that with a mouse? I am having difficulty believing so because the lines look drawn like with a pen, and am curious on what you used. 

I play with Wacom drawing pads.  They make drawing lines easier.  

ADsioFL.jpg

The small one functions fine (like below).  But for a bit more elbow room, I got a medium sized one (8"x5").  At the time, I thought $80 for the small, and $160 for the medium one was ridiculously expensive.  But now that I've added a dozen Tamiya cars, it doesn't seem expensive anymore.  Funny how everything is measured in increments of Tamiya cars...

dsynWJAh.jpg

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46 minutes ago, Juggular said:

I play with Wacom drawing pads.  They make drawing lines easier.  

ADsioFL.jpg

The small one functions fine (like below).  But for a bit more elbow room, I got a medium sized one (8"x5").  At the time, I thought $80 for the small, and $160 for the medium one was ridiculously expensive.  But now that I've added a dozen Tamiya cars, it doesn't seem expensive anymore.  Funny how everything is measured in increments of Tamiya cars...

dsynWJAh.jpg

Gorgeous self portrait you fine looking Jug of loveliness ;)

  • Haha 4

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