It's always nice to have a foundry handy to make some parts right? I built this furnace from scratch, worked on it off and on for about a month. It has been quite helpful, I cast some new gears for my lathe which was missing a few teeth. It was easier for me to cast them rather than index and cut the teeth. I also use the furnace for heat treating metals also. If you've never done it, you should read up on it, there's a lot more to it than you think. There are alot of changes that take place in the steel during heating & cooling. Depending on the grade of steel you'll get different results in hardening depending on the carbon content.

Here's a pic of the furnace looking down into it from the top, this was taken while the refractory was in the curing stages.

Here's a pic of the furnace in operation, that is molten aluminum in the crucible, just about ready to be skimmed.

This is just an overall view of the furnace, not much to see really as it's fairly simple, but very useful tool.