I have mdae a wood to charcoal machine( Its not my design ). What you do is place wood in the hopper, and if you stay there in a few moments, wood will convert into charcoal, and go to a chest. The chest has 64 charcoal for 140r, making it easy to buy the coal. Res number for machine: 930 on smp1.
With these machine, people can just trade in there wood logs and get charcoal easily. Lots of people like fast and easy ways. Not many people would want to go to there res and do it the old fashioned way, sadly. The machine will soon have free use, meaning you will not have to pay any charcoal!
It seems like you could run the output back into the Furnace for fuel. The Furnace would need an Access sign since the Furnace would keep itself filled with fuel and the user would need to be able to retrieve it. Or maybe you could use a Comparator to limit the amount of fuel it pulled out of the Chest. Then the only thing that someone would need would be a starter piece of fuel, which you could sell from a nearby Chest or they could use one of their Logs to get it started.
