Thanks for the input. Your log is very informative. I just ordered some proper connectors. I am building this furnace using as many of the old parts I have been collecting over the years as possible. Trying to use up the old parts I have salvaged.

I just began some preliminary testing of my furnace. It heated to 1200˚f in about 10 minutes, then I shut it off. The high setting draws about 24amps at 240v, about 5700 watts. There is also a LOW circuit which should draw 6 amps at 240v, about 1400watts, but the old contactor I used in that circuit was faulty so I do not have data for that yet. I am going to pause testing until the low circuit is working and the thermocouple connector installed.

From your build log, the 1400 watts in the 3.5 liter chamber works out to about 410 watts per liter, seems about right. Live and learn, the 5700 watts is over 1600 watts per liter.

I shut it down very soon after I removed the vent cap and peeked inside.

Click image for larger version.  Name: Hot Furnace.jpg  Views: 62  Size: 96.3 KB  ID: 48956

I have another question. My thermocouple has a nice braided steel shielded cable. But it is longer than necessary. Should I cut that cable then use the cut off piece inside the control box from the jack to the controller. Guessing the conductors in that nice cable are special also.