Recently in passing we spoke about a pit carburizing furnace located at a commercial heat treater in Germany by the name of REESE which is the largest we have ever seen. In response a fellow from gear manufacturer David Brown in Santasalo, UK sent us these photos of their captive heat treat department. With the ability to carburize gears up to 3 meters in diameter (9′), 3 meters high and with a weight capacity of 18 tons it is an enormous furnace, however still smaller than the one at REESE.