I played with this for educational fun.
go over to my models and look for "surface fun", I just posted it.
Also there is also a vase model that I posted some time ago that I used as reference in making this sprocket or gear.
Roll it back and see each step along the way and how they build on each other.
There are some other hidden features that are used only for construction just because they are hidden does not mean they can be deleted.
Hope this helps