couple methods I use:
- I use K&S Metal Hex bars and cut them to appropiate sizes when I need them to be metal.
- If plastic is suficient I use Raboesch hex plastics and cut them to size.
- If I need special size hex heads I use bar stock and convert it to a hex using a dividing head as explained above.
- If I am in a hurry, or I need a special and detailed bolt, and plastic works again, I make a master of the bolt head then make a mold of it out of resin. then I press melted sprue in them. think of it as a poor mans injection machine... (I use this method for Armor and Gundam building)