Create-Above & Beyond Iron farm. Generates iron by grinding cobblestone into gravel and washing into iron nuggets.
The farm works by picking up cobblestone pillars with a sticker contraption and putting them in a central pillar where they break the previous pillar that was placed there before. Cobblestone flows upwards through the blocks and get funneled into the grinders at the top, and then get washed into iron nuggets.

This design is based on one from DeltaV Where stickers are used to move lines of cobblestone. Their farm uses tier 3 machines while mine uses tier 2 machines. There's 3 lines of cobblestone instead of 2 and the timer speed is 25% faster resulting in about 2x the amount of iron gathered.

IMPORTANT INFO:
The project red wiring/timer are not included in the schematic and water and lava can't be placed with the Schematicannon thus these must be placed manually. If you want to see where the liquids need to go, I will try to explain it here but you can also load up a creative world and place the blueprint directly there as that will place the liquids.

Project Red wiring is used to (un)power the stickers at each rotation. Add wiring behind the observer leading to the stickers as well as under the main pillar. (view the gallery for guidelines)

Power this wire once manually to activate the stickers.

Add water on top of the tower to flush cobblestone to the drawer and Waterlog the bottommost stairs and then the topmost stairs to create a waterfall. Place a lava source block opposite to the entire waterfall. Also add a water source in front of the encased fan below the grinders.

There is a windmill at the back of the farm that powers the contraption at the bottom. Right click the windmill bearing to start.

There is a furnace engine at the back of the structure, It must be supplied with a constant source of fuel to keep this farm running. Only a single item for smelting is needed as a fan will pull it out of the blast furnace constantly.
For some reason the belt on top of the furnace engine is turned sideways in the schematic and I wasn't able to fix it. It should be changed manually so that the shafts face upwards.

The project red timer is not included in the blueprint. Place a timer with a 1.50s clock facing into the redstone link to start the farm. Blocking this timer will turn off the farm.

End of Important info

The farm is not perfect and has some losses, some cobblestone may end up being thrown outside of the tunnel, this was causing issues where the chute on top of the furnace engine became filled with cobblestone so I replaced it with a filtered smart chute.

Be careful when changing things about the farm, notably the contraption. You may end up with the contraption rotating the wrong way and placing cobblestone in the space around it. Always turn off the farm by stopping the timer before changing this stuff.