These are my attempts at automatic smelting machines. I didn't like any of the designs on YT so I made some of my own. If you've never seen or heard of these before, basically, you have a minecart that passes over the hoppers depositing your ore/block to smelt and another that passes over another set of hoppers depositing coal. Then another set of hoppers pulls the smelted items from the furnaces and deposits them in a chest. The bigger you make them, the more they can smelt at once.

Machine 1 is designed to be more functional than pretty looking so it has the input and output on the same wall for ease of access. It is the one I've chosen for my Survival world.

Machine 2 and 3 were designed for looks and to be compact so their inputs are inside the guts of the machine. Machine 3 is the same as machine 2 except the minecart stations were moved outward and lights added that flick on and off as the minecart passes by them. This lets you know the machine is running and the cart isn't stuck.

Additional Notes

Texture pack: Pixel Perfection

EDIT: Found a small flaw in Machine 1's design. One of the levers was powering a hopper preventing it from moving items. Fixed it and updated the schematic.

EDIT 2: Updated Machine 3's schematic file to remove the grass from it.

Edit 3: Updated all the preview images. Put a lot more time and effort into them to better display the project and improve the overall look of my account.