Grinding my own feed.

I have a small but growing feedlot that I finish some cattle for freezer beef. (10-15 currently). It's in an old 3 sided hog barn that I've converted to work for cattle. I'm currently buying a complete feed ration from the local feed mill. Going into my third year of this endevour I'm considering saving myself some money and grinding my own feed. I have acces to shelled corn, or rather I would purchase it from a local farmer and run it through a feed grinder. Does anyone do this themselves? I know nothing about grinding and making my own feed but am strongly considering buying a pull type grinder mixer. Any help would be greatly appreciated!

Grinding my own feed.