Lost spinner from one of my motors when the new battery slipped out during flight and i lost control and quad crashed. Went shopping online for new spinners but am confused (as confused as a newbie can be) because the spinners i see online are different, they seem to attach to shaft of motor while mine just screw on to the shaft (850kv Avionic motor from RCBazaar, nope, they don't stock any spare spinners) . Am attaching pictures of motor and one of my spinner. Is it ok to use normal nuts? am afraid if the fly off they might hurt someone or something. I use threadlocker but this was a new battery and new set of propellers so though will take them for a spin and come back and apply the threadlocker. Any help and gyan about these spinner will be much appreciated and if some one can tell me where to get this type of spinner will be obliged.

Thanks everyone.

Measure the diameter of the shaft (should be a little bit less than 6mm)
Just use any M6 nut as a spinner.

You can use 2 regular nuts tightened on top of each which makes it almost impossible to come off mid flight.
Alternatively you may also use single Locknuts like these:
http://stores.ebay.in/Indian-Hobby-Shop/_i.html?_nkw=locknuts&submit=Search&_sid=1125855133

Don't use threadlocker in any case. You would have to change props from time to time in the begining.
Just tighten them a bit hard enough (not too much). Would be fine.

Try at RCD, http://www.rcdhamaka.com/index.php?main_page=index&cPath=56&sort=20a&page=2. Maybe you may have to call them up with details of the size and type of the threading, like the shaft dia & clockwise/anticlockwise tightening, thread pitch, etc for precise purchase.

You can alternatively can use an ordinary nut too with additional lock nut, but might add weight as they would be of alloy steel rather than alloy aluminium.

Thanks Ashok, will try at RCD. Thought of using ordinary nut or lock nut but the space left for after putting propeller in shaft is about 3 to 4 mm while lock nut i are about 6 mm high, so am bit afraid of using them, but might use them with threadlocker if not anything else. Just a thought don't know if i am right, if i buy any prop adapter (regardless of the shaft size) the spinner on top to tighten prop on adapter should be same size as the one i need because same props that fit onto my motor are normally fitted on the adapter, i can just not use the prop adapter, just its spinner. Am i correct?

Thanks, bought a lock nut but it's 6mm high while the threads that remain on this motors shaft are about 3 to 4 mm. Wondering if i should still use it with blue threadlocker or will it be still dangerous? if i buy any prop adapter (regardless of the shaft size) the spinner on top to tighten prop on adapter should be same size as the one i need because same props that fit onto my motor are normally fitted on the adapter, i can just not use the prop adapter and only use its spinner. Am i correct?

With such an wide array of hardware parts, it is difficult to say the same prop size adapters have the same unless they all follow a set standard. If they are not too hard on your pocket, then you can as well give a try buying it.

You can visit a few local hardware stores near to your place and check around, they might have some nuts that might be apt, if not with the parabolic spinner head. If your quad is not intended to fly at high speeds over a larger distance then it should not be of a big issue. Again, I am not a multicopter user/expert, so please make a informed decision.

EDIT: Also note the thread tightening direction [say for eg.CW] should be opposite to the direction of the operation [CCW], else due to torque effect the nut will be set loose and fly off. Again not sure the motors used/supplied/manufactured are made with this kept in mind.

True, was just browsing there seem to be many types of prop adapters, hard to say which will be correct. Will give a go to more hardware stores and see if i can find a shorter nut. Thanks again.

Extra thread on the motor shaft won't create any issues.
Don't worry, Thread-locker is not required in any case. Just tighten the spinner/nut/locknut a little bit tight (not too much though). It won't come off.

Yes, you can just use the spinner from the prop adapter.
Just make sure that the thread on the motor shaft and the spinner from the prop adapter are same size.

Thanks again, but extra thread remain not on the shaft but on the nut, it only half goes in, that's what worries me. Will try and see if there are any matching prop adapters. Just found out by searching the web that these are DJI type spinners, seems the threads on shaft and no need of prop adapter comes in DJI motors and mine seems like a clone of that.