pinion slip
 

i guess this is a newbie question but i for what ever reason am having a hell of a time getting pinion gears to stay put. I have tried the set screw alone. I have tried locktite on the set screw, i have tried the locktite on the shaft. I have tried locktite on the shaft and the set screw haha.. other than grinding a flatspot on my motor shaft what are some other ideas or tips comes to attaching these large mod 1 size gears.




ps: tony i know you will see this. ill take pics of mug as soon as my fans come in. you'll dig...

With the instant torque delivered by these brushless systems, grinding a flat spot is almost mandatory. About 30 seconds with a Dremel is all it will take...

GOTTA do the flat spot!

Yep, no flat spot = no grip. What I usually do is remove the rotor from the motor, shove the shaft through a plastic bag, stick the other end of the rotor in the vice, and dremel a flat spot along most of the length of the shaft. If I can't get the rotor out, I still use the bag, but I attach the three motor leads together (to help keep the rotor from spinning), and lay the motor in the vice (but don't clamp down on it). So far all of my flat spots look incredible :005:.

I just taped up the end of the motor with just the shaft poking through, grabbed hold of the shaft with a large skinny set of hemostats (AKA roach clip), then took a dremmel to the shaft as I held the motor and hemo's on the table. Got a perfect flat spot!

Wow, you guys go through greater lengths than I do! I just tape the motor holes, grab onto the shaft with my fingers and dremel away. However, I do dremel so the wheel spins along the shaft so it doesn't try to spin it.

ah ok .. i was worried that it may terminate a bearing by being unbalanced but it seems like its a non issue. thanks

i had to use flat spot (just taped the motor) + blue loctite. without loctite no chance

If you are worried about balance issues, just remember that the set screw helps offset the imbalance caused by grinding the shaft. In fact, you probably have more imbalance if you DONT grind the flat spot because of the set screw...

... which could cause slight vibrations leading to the set screw loosening up.

Ideally, if you KNOW what gearing you are going to use, I would drill a counter-sunk shape hole into the shaft for the set screw to sit inside. That would be the best hold, IMO. I have not done this however, just a thought.

This is what i do; push the shaft through a plastic bag, and wrap the rest of the bag around the motor. don't push your dremel too hard, and a small notch is all you need.

Yeah, same, I took the rotor out of the motor, and pushed the shaft through wide masking take and wrapped the rest back over the rotor to prevent filings from being held on.

Why would you take the rotor from the can? this only increases the risk of damaging and it's more exposed than it is in the can.

The 'crater' works good for me. I make a short, shallow flat spot, then bore in a dimple with the tip of a dremel grinding stone. (I just grab a dremmel and a motor and go at it. yes grind at right angle so the shaft doesnt spin.)

I then blow off any metal dust that may have stuck. (I'll do a plastic bag next time :) )

I do not like long flat spots, they unbalance one end and make the shaft wobble. Also, I use the motor fror braking and a flat spot always seems to leave a little 'play' and this ALWAYS loosens the set screw for me.

This with plenty of LocTite is the ONLY thing that works for me so far.

Because I have a 540C version, I can, and it's easier.

I wonder if it would be a good idea to put a flat spot on both sides of the shaft to make it balanced?

Like said in a previous post, the set screw in the pinion makes it a bit unbalanced as it is. Grinding a flat spot on the shaft helps negate this imbalance as long as it only as long/deep as it needs to be. Truthfully, I really never gave it much thought before. Of course, if I was eating spurs/pinions, I probably would look closer at this.

ya.. sounds like it really isn't that big of an issue cause im guessing becuase of the small scale and misc. other factors. Coming from just having built a Honda engine to hold 500+ hp i guess i can be a little paranoid about tolerances.

ps.. no more slip with notch "buzzed" in

[QUOTE=BrianG]Like said in a previous post, the set screw in the pinion makes it a bit unbalanced as it is. QUOTE]


Have you balanced a pinion? I was thinking that the set screw might actually be lighter, It has a hole in it, and is pushed toward the center. Course, different pinion/set screw types might change this too. Just wondering...

Just got a MMM 2650 combo, wanted the 2200 but hobbywarehouse shipped the 2650, anyways its in my E-revo with a 54t spur. The motors shaft already has a flat spot and I have the set screw as tight as I can get it, however after driving the truck for a little while the pinion gear slides forwards and starts to chew up the spur, is there anyway for me to set the pinion in better so it doesn't slide forward?

Are you using threadlock on the set screw? You could try filing down the end of the set screw a bit so it has a larger contact area with the motor shaft.

Make a crater
 

Nothing works for me except a 'divet'. Make a small flat spot, if no flat spot already. Then use the tip of a stone dremel thingy (This will wear it out after a few of these) to put a crater just a little bit bigger around than the set screw. Then use threadlock. The set screws balance should be ofset by the flat spot. Make sure to place the 'crater' in the right spot, or youll have to make another on the other side. I have a 5 cell (lipo) brushless losi 8ight from 2006 all custom. this works!!! Good Luck

The cup on the bottom of the set screws typically used on pinions has sharp edges. Over time (tightening and loosening the set screws) these edges can wear out so they no longer "bite" into the motor shaft. A new set screw is often a worthy fix, and threadlock is always a must.

Thanks guys, BTW Bliporacer the set screw is brand new Just got the motor, pinion, set screw yesterday, but I'll see about getting some blue thread lock, would it work just to mark the area where i want the pinion on the shaft then take a file and file down a small spot or at least to give it some more bite area?

you need red threadlock:whistle::lol:

Ehh just weld it on there...

All I use is blue and I've never had a problem! Don't expect it toi hold 5 minutes after you put it on though! I use blue loktite exclusively, red is for permanent lock, nothing RC is pemanent, I always change things up and the red can sometimes be tougher than the hexes!