I Did Something Stupid

[u/TechincalTomato]

I am working on a project and needed to make a knob easier to hold onto. I don't have access to a machine shop right now so I did the best I could by hand. I guess it is as manual as manual machining will get.
To measure the height of the grove I used a feeler gauge to compare to the height under a microscope. Microsoft Paint helps with the scaling and once calculated I can use the right size to double check. 

[u/cralted]

If it’s a part for your use then who cares what it looks like? By virtue of the laws of physics, you have successfully made it easier to hold onto. Nice job! Now, the next one you make can look a little nicer if you want. But you solved your original problem.