| 1960 | In 1960, TANDLER bought their first heat treatment oven for their production of gears and gearboxes. |
| 1993 | Since then, TANDLER enlarged their offer and, in 1993, founded their own heat treatment plant in the North of Germany: Härterei TANDLER GmbH & Co. KG. |
| 1999 | In 1999, they got their own plant right beside the gear and gearbox manufacture of TANDLER Zahnrad- und Getriebefabrik in order to be able to buy more ovens and offer their services to other companies. |
| 2004 | In November 2004, the German aeroplant manufacturer, Airbus, and the Association for German Aviation, Astronautics and Equipment Industry (BDLI) awarded Härterei TANDLER with their certificate. Since then, Härterei TANDLER is contractor of German Aviation. |
