Pinion Failure/help!

[TurboTeg512]

Ok so I went to take my pinion gear off and BOTH of the grub screws broke. I don't know what to do now. I fear I may have made a $140 mistake with trying to change my pinion gear. I don't know if im able to drill them out or not, but they need to come out. Does anyone know what EXACT size they are? I believe theyre M3's... (3mm) but I need to be sure. And will this damage my motor shaft? Should I avoid drilling and try something else? Any help/suggestions are welcome and appreciated.

 

[JvG]

So you have a pinion with 2 grub screws?
Never seen that. Do you have some pics?

 

[Lingerfelter6]

I am curious as well. Never came across pinions with 2 set screws. That said, you could try using a reverse drill bit to get it out. I had some success with that, have not tried it with set screws though

EDIT : Didnt read correctly. If the screw has broken, this method wont work

 

[Jeremy in WI]

Be careful! I just had to drill the grub screw on one of mine and I went too deep. Got into the shaft... I contacted hobbywing and they don't offer replacement armatures for mine (I don't know about other motors). If you drill them, go slow. Check for pinion movement often because theres not much space between done and too far. If you are using 2 grub screws at once, that's not necessary. Next time just use 1 on the flat side of the shaft. Good luck, we're all counting on you!

 

[TurboTeg512]

So you have a pinion with 2 grub screws?
Never seen that. Do you have some pics?

Yes they did it on the Nero motors. The shaft has 2 flat spots as well. Ill try to get some pics

 

[Zgills1]

This happened to me while I had the stock pinion on the motor shaft. I had to take a dremel to the pinion set screw.. and be extremely careful not to ding the motor shaft. Going slow is my best advice.

 

[Mongoose]

If you have to drill it out, go slow and step up the drill bit sizes...don’t try and drill it in one shot. Yes, don’t nik the motor shaft but if you do it isn’t the end of the world, the pinion with a set screw in one side unbalances the rotation anyway, then even more if you use a pinion with a larger set screw. Im more worried about drilling out the threads in my pinion when I do this. When you think you are getting close to the shaft, slow down and check often but if you do happen to slightly drill into the shaft it will not wreck the motor....that is unless you drill halfway through it lol.

 

[TurboTeg512]

I am thinking of using a Dremel with a small bit and basically reaming it out. I have some cutoff wheels but I imagine it would take me forever to cut through the hardened steel of the gear itself.

 

[Mongoose]

I don’t recommend using a Dremel to ream the screw out, the dremel oreintaion to the screw is too unorthodox and you won’t be able to drill straight. You will need a drill to do this...but if all you have is a dremel then I would recommend a cutting wheel to cut notch in the set screw head to allow you to use a screwdriver. The smaller the wheel OD the better to minimize the amount you cut into the pinion itself.

You will be surprised how fast that wheel will cut.

 

[cootertwo]

Yes, I have a pinion with 2 set screws on something around here. I used both, as I figured it would help with the balance. As far as your problem, If you mean the heads are just stripped out, I'd try drilling first. if that don't work, I'd sacrifice the pinion, but slowly cutting with a dremel tool with a cut off wheel. IF you can get to it! I'd make a cut right on each set screw and keep getting wider, until it's gone. I can't see how you could "break" one of those screws, they are usually completely inside the threaded hole of the pinion.

 

[JvG]

Yes they did it on the Nero motors. The shaft has 2 flat spots as well. Ill try to get some pics

Ok thanks, i can't give you more tips than other members did, good luck!

 

[sentonist]

I would recommend what mongoose said here, I've never broken the head of the pinion grub screw, but I have broken screw heads before, and using the cutting wheel for a dremel to notch a line on top of the set screw, and you can use a flat-head screw driver, and everything should be dandy, but you'll likely need a new pinion at that point. In some cases if the screw doesn't have much force on it, I would take some super glue, and put a little dab of glue on the head of the screw, and put a screwdriver in that dab of glue, wait for it to cure, and in some cases it does work, but I don't think it would be the best bet for this scenario.

 

[TurboTeg512]

I would recommend what mongoose said here, I've never broken the head of the pinion grub screw, but I have broken screw heads before, and using the cutting wheel for a dremel to notch a line on top of the set screw, and you can use a flat-head screw driver, and everything should be dandy, but you'll likely need a new pinion at that point. In some cases if the screw doesn't have much force on it, I would take some super glue, and put a little dab of glue on the head of the screw, and put a screwdriver in that dab of glue, wait for it to cure, and in some cases it does work, but I don't think it would be the best bet for this scenario.

See that's the problem... Ive already done that. that's how it ended up breaking. When I notched the screws, I slowly started wrenching on them with a flathead screwdriver and one side broke off of each of the grub screws.

 

[Zgills1]

When I mentioned using the dremel tool, I had to cut the pinion off. I basically made a cross pattern like a + sign. Eventually the set screw just fell out. This was due to the infamous RED loctite that was used at the factory. The dremel tool cut right through the pinion (whole process was maybe 5 minutes) and yes the pinion was destroyed. That’s why I keep extra laying around. Hope you can get it off with ease.

Do yourself a favor and use blue loctite on future pinion set screws, and just use a very small dab.

 

[TurboTeg512]

When I mentioned using the dremel tool, I had to cut the pinion off. I basically made a cross pattern like a + sign. Eventually the set screw just fell out. This was due to the infamous RED loctite that was used at the factory. The dremel tool cut right through the pinion (whole process was maybe 5 minutes) and yes the pinion was destroyed. That’s why I keep extra laying around. Hope you can get it off with ease.

Do yourself a favor and use blue loctite on future pinion set screws, and just use a very small dab.

Yeah I know what you meant. And I always use either blue Loctite or thread locker from hobbytown.I did end up getting it off finally. I did not use the x pattern, I tried drilling them out to no avail. My bits just kept dulling out cause theyre cheap. so I ground them down slowly and ended up knicking the shaft like a putz. Then I had to buy an 18t pinion from hobbytown that is too big to fit on the motor. I managed to make it work anyway though. Thanks for all the help guys. I ran into another problem ill be starting a new thread on lol

 

[Mongoose]

Good deal! Sucks about the pinion but at least you got it off. I’ve knicked the shaft too...no biggie.