Algodoo

While playing with it, there were a few times when the rotor and stator would separate, and Algodoo repulsive forces would prevent them from realigning into proper position again. In that case, I had to restart the scene. Failure occurred when I released movement of the rotor when the green fins were directly over the red fins (at the exact center point of the left/right rotational forces) either with an arrow key, or when I used the drag tool.

Well done this type of coupling is used in TONS of stuff
besides being usefull for indexing

Xray,

Thanks for the feedback. The joint assembly fails if you are not close to an indexed position. This is because I purposely made the axle hingeConstant very small. When checking the centering ability, it is best to use the move tool.

s_noonan - The Move Tool or the DRAG Tool? If I attempt to rotate it with the Move Tool, it only translates the rotor, and will not let me rotate it.

The Move tool since it disables collisions while moving. Right click the rotor if you also wish to rotate it. Usually the Hirth joint is very close to its final position before it is assembled or clamped. It is similar to assembling a spline. You normally wouldn't try to assemble a spline by jamming the teeth together. It's like trying to put a square block into a square hole by forcing the block through diagonally. This scene falls short because it allows a user to try to assemble the Hirth coupling when the rotor is in line with the stator. I may fix this.

I didn't know that you can rotate with the Move Tool by right clicking. Hey, I learned something new today!!!

The scene works better and is now more robust. Good job!