Figures with a recurrent shape that pivots around a center are easily generated with the spin tool in the edit mode of the 3D viewport. However, since it seems like you might benefit from "editability" of the shape I would suggest a different approach.

1. Mirror a cube and model a single gear tooth.
2. Add an Array modifier to the object.
3. Set its count to 14.
4. Add an empty object where you want the center of the gear
5. Rotate this empty by 360/14 (Blender will automatically calculate the outcome of that fraction)
6. Set the array only to "Object Offset" and select the empty.

The result should be as follows:

Figures with a recurrent shape that pivots around a center are easily generated with the spin tool in the edit mode of the 3D viewport. However, since it seems like you might benefit from "editability" of the shape I would suggest a different approach.

1. Mirror a cube and model a single gear tooth.
2. Add an Array modifier to the object.
3. Set its count to 14.
4. Add an empty object where you want the center of the gear
5. Rotate this empty by 360/14 (Blender will automatically calculate the outcome of that fraction)
6. Set the array only to "Object Offset" and select the empty.

The result should look like this: