| 1934 | Founded by Mr. Paul Kehren. Dealer for alloyed steel and subcontractor for "Deutsche Bahn" - railway company. |
| 1949 | Development and manufactoring of rotary table grinding machines. |
| 1961 | After the death of the founder, the company is taken over by his son Helmut Kehren. The vertical cylindrical grinder Ri is developped and delivered one year later. |
| 1980 | KEHREN equips the first grinder with CNC-control, Siemens Primo SG. |
| 1989 | Development of the backlash-free direct drive for grinding curves and serrations for example. The first machine is delivered in 1990. |
| 1993 | Helmut Kehren dies, the company is taken over by Dr. K.-P. Neumann and by Mr. R. Krämer, who becomes executive director. |
| 2001 | Presentation of the first Ri grinder with Y-axis in the side support. |
| 2002 | Mr. Ulrich Krämer is appointed technical director, Bruno Mies becomes commercial director. |
| 2003 | Development and presentation of the grinding machine in portal design. |
| 2004 | Presentation of a Y-axsis in the grinding head for serration grinding. |
| 2005 | Enlargement of the Ri series by the Ri 5 model. |
| 2006 | Presentation of the Ri 8-4 grindturn model in inclined-bed design (turning - grinding). |
| 2008 | Enlargement of the machining possibilities by hard milling. |
| 2009 | 75th anniversary of the foundation of KEHREN. To this day, KEHREN is in privat hands. |
| 2011 | Presentation of the Ri series with direct drive in the X-Axsis for highest machining accuracy with "no wear" behaviour. Introduction of a robot tool change system. |
