Sinusoidal milling - GIF

Sinusoidal milling.

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Previously:

https://www.homemadetools.net/forum/...034#post199068
https://www.homemadetools.net/forum/...106#post195376
https://www.homemadetools.net/forum/...153#post187994
https://www.homemadetools.net/forum/...172#post188046
https://www.homemadetools.net/forum/...374#post188896

I wonder what that part is to be used for?

My neighbor had his Harley Davidson engine fins done that way. Looked great

Greater surface area for more effective cooling, but requires more air flow because the wavy fins impede the passage of cooling air. Is it really worth the effort for the sake of appearance?