I have seen this post here that asked the same question, however, the user forgot to use one component (collar). I have similar components and even when I mount everything correctly, the mount is loose. I bought a kit for a quadcopter and 3 of the 4 propeller mounts are loose.
Like you know how the propeller should turn when the physical motor turns. well the props also turn by themselves on the surface of the motor since it is not tight there. I have tightened the nut of the propeller (cone shape thing) with some pliers pretty tightly, and that stops the propeller nut from flying off, but it doesn't stop the entire mount from flying off.
How do I tighten this? I tried to tape the motor stick thingy that the props sit on top of but it peels off as i slide the propeller mount on it. I have also added some images if needed and in the first one, you can see the how it sort of slides vertically on that motor stick thingy. Thanks!