How to stop motor shaft nut from coming off?
- Thread starter azad
- Start date
scootergrisen
100 W
- Joined
- Feb 26, 2018
- Messages
- 154
Maybe a woodruff key would help.
And maybe a nut with like 3 times more area to touch the aluminium.
And maybe a nut with like 3 times more area to touch the aluminium.
Is there a key in that keyway? Is the shaft and sprocket tapered?
As a first-try solution I'd thorough degrease all parts and use loctite on the threads. Blue is normal strength, red is much stronger but beware you'll need to apply heat if you ever wanted to get it apart again.
As a first-try solution I'd thorough degrease all parts and use loctite on the threads. Blue is normal strength, red is much stronger but beware you'll need to apply heat if you ever wanted to get it apart again.
azad said:
Is the sprocket deeper than the one that came with the motor? It looks like the nut would usually tighten up against the shoulder of the shaft where the threads end, so having it only contacting the sprocket may make the nut do the work that the key would normally do.
aroundqube
10 kW
- Joined
- Mar 12, 2012
- Messages
- 577
I would try a key long enough to go to the end of the keyway, and use 2 heavy vibration locknuts. Place a thin one on second, to act as a jam nut. These parts are available here : https://www.mcmaster.com/hex-locknuts
The shaft is right hand threaded. If it's on the right side of the bike, motor torque will be applied in in a way that tends to unscrew the nut.
Usually, this tendency would be mitigated by the key keeping the sprocket from rotating on the axle. But it looks like you don't have a key on the motor shaft. That's the part you need to fix. The retaining nut is not for keeping the sprocket from spinning on its shaft. It's just for keeping everything stacked up together.
Usually, this tendency would be mitigated by the key keeping the sprocket from rotating on the axle. But it looks like you don't have a key on the motor shaft. That's the part you need to fix. The retaining nut is not for keeping the sprocket from spinning on its shaft. It's just for keeping everything stacked up together.
azad said:
That shaft has been eaten up because there wasn't a key to keep it from spinning in the sprocket. The sprocket bore may be damaged, too.
If it were my motor, I'd get a new one, (and a key for the shaft keyway). The sprocket needs to fit tightly on the shaft.
John in CR
100 TW
It looks used enough to graduate to a more efficient more quiet brushless motor setup.
aroundqube
10 kW
- Joined
- Mar 12, 2012
- Messages
- 577
could be a half moon or Woodruff key : https://www.mcmaster.com/machine-keys
azad said:
I assume you mean the sprocket hole is 11mm on the inner side and 10mm on the nut side?
Otherwise, the seller sold you the wrong sprocket.
Edit: I don't see the gradual increase in diameter in the picture of the motor shaft. I see the step.
dogman dan
1 PW
Nut should stay on better, with the key in there. Locktight it too.
scootergrisen
100 W
- Joined
- Feb 26, 2018
- Messages
- 154
There is a problem with the chain on picture 3.jpg in case you did not know.
