The Machining Table is an Industrial-level Production bench that crafters will use to produce a number of items as well as disassemble mechanoids. It can only be constructed after machining has been researched. Like most production benches, the machining table must be configured with one or more bills before a crafting colonist will begin work.
The "disassemble mechanoid" bill is fulfilled when a colonist brings a mechanoid corpse here to be converted into usable materials. This will produce some steel and plasteel.
Craft Artillery Shell
There are many other bills that can be used to produce rifles, other advanced weapons, Power Armor, Power Armor Helmets, and armored vests.