How Much Runout?

[Marvsdrone]

I have a very tiny vibration in my P3P.
I've balanced the props, the gimbal is fine, no looseness there.
I've clamped a pencil to each arm, barely touching the motor bell, then spun the motor.
Three motors leave a line all the way around but the fourth skips about half way round.
Was wondering what is the acceptable run out for these motors?
.001" or .002" would be acceptable, I think.
A question for the DJI office?

 

[Erised]

I don`t know witch internal clearance DJI chose for their bearings. A 604 bearing (NTN) with a CN clearance(normal) is from 0.00015 to 0.0004 a C3 (more) is 0.0004 to 0.0008 a C2 (less) is from 0.000 to 0.00023 plus any other clearances for fit into the housing or shaft, usually the rotating part is a press fit and the stationary is a slide fit. Runout comes from the fit from the outer race to the housing, internal bearing clearances, shaft to inner race and a bent shaft. One or more of these added will cause runout and at around 6K rpm it does not take much. One of the factors a bearing will be chosen depends on the amount and type of thermal expansion that will affect the desired internal clearance.

 

[Marvsdrone]

Thanks.