Thanks for the reply. Sorry I didn't get back for a while. I've been completely swamped lately.
Well, I used a AX-18A Dynamixel. Which, worked, but because I was not using a good joint, it didn't work well at all (the joint was unstable and probably did a bit of damage to the motor, or at least damaged the bracket).
Since I'm an almost complete newb to robotics, I didn't know about bearings. Now I realize that whenever you need a strong, stable and durable joint, you use bearings.
But, since I had this idea, I decided not to use a rotational joint like that. I'm planning to use a jib arm instead. I'd like to say what the application is
but I'm afraid it's probably a bad idea because it will be a new product, and I don't want to broadcast the idea.