You can see that on the circular aluminum brake part (don't know the proper name), it has 5 holes drilled. I called the company and they said they have CAD files and it is done in mass. I don't have those CAD files and I am not a CAD expert, nor do I have a machine to cut it.
I want to know the best way to measure (with basic relatively inexpensive tools, if needed I'll buy more), and replicate those holes with high precision on the sprocket. As you can tell, this is going to spin, so any measurement that is a little bit off is going to make the sprocket wobble.
The sprocket is not the same exact size as the aluminum brake part.
I am not looking for measurements. I am looking for how to measure. Not the fish itself, but I want to learn how to fish.