Thanks to Fierce_Deity for the Bog-Iron post. it was the inspiration for this post.
viewtopic.php?f=48&t=59726
start with a draft furnace: https://www.youtube.com/watch?v=u7wAJTGl2gc this basic design seems to be common across a number of cultures.
you can add a bellows to improve effency: https://youtu.be/RuCnZClWwpQ?t=1h7m58s this is an African method but is included to show Low Tech Possibilities.
they would be fed with charcoal from a charcoal kiln: https://www.youtube.com/watch?v=GzLvqCT ... QxjPs7q3CJ
with a natural draft furnace, i would increase the time to about 4x of the smelter, but with an added bellows it could be cut to 2x with active use, like cooking on the spit can be sped up by turning.
The charcoal Kiln would produce charcoal, which would be created from sticks and not blocks or boards, and would produce 1 charcoal for every 4 sticks and could be used as 4 ticks of fuel in ovens, campfires, and cauldrons, but only fire for a single tick in a draft furnace. I know that a tar kiln produces "Coal" which is essentially charcoal, but i don't want to overlap the uses or nerf the use of the Tar Kiln.
Iron could be found via bog-iron and Termite(or ant) mounds. both of which would need to be smelted in the Draft Furnace.
Basing the items available off of a somewhat primitive technology, i don't think that armors or many weapons would be able to be made in this manner, but should be limited to spears, arrows, and tools. all items would be set between stone and metal possibly called "Primitive". using the primitive metal for fine items like hooks should be impossible due to the primitive and impure nature of the materials. technically the metal can be hammered out on a log with a wooden club.
an extra tool could be added with or without the addition of this method of smelting:
Sickle: a one handed crop harvesting tool. half the speed and stamina drain reduction of the scythe