Factory Iron Knife factory Machine Metalworking Solingen

Sharpening machine (“Blaupließtbock”)

The “Blaupließtbock” from the 1910s is in use in the knife factory Windmühlenmesser Robert Herder in Solingen (Germany North Rhine-Westphalia). It is an electric sharpening machine used to create a special finish for blades: the so called “Blaupließten” (Blue-sharpening). It is usually operated by employees who have mastered their craft. This work is one of the most complex techniques of the traditional craft of knife-whetting in Solingen.
The surface of the blade is freed of the rough stress marks by using a fine abrasive paste on rotating leather or felt discs. To do this, the worker presses the flat side of the blade with the strength of his/her legs against the fine grinding wheel. The blade receives finer and smoother rills which improve the cutting quality and durability. At the same time small, unwanted blemishes are corrected and the sharpening angle is narrowed a bit. A blue or rainbow-colored gleam is characteristic for the blue-sharpened blades.
The typical sounds made by this work process result from the sharpening of the blade on the grinding wheel.
The “Blaupließtbock” is located in the knife factory Windmühlenmesser Robert Herder in Solingen (Germany, North Rhine-Westphalia), which was founded in 1872. Today the enterprise is in its 4th generation, headed by Giselheid Herder-Scholz. It has maintained techniques and methods of manual knife-making which have vanished more and more with the growth of mechanical fabrication.

In Solingen the production of blades has a long tradition. As early as the 14th century blades were made in large numbers in Solingen. Until the end of the 19th century the entire economy of Solingen was dominated by the cutlery industry.

Sound recordist: Konrad Gutkowski/Julian Blaschke
Photographer: Konrad Gutkowski/Julian Blaschke
Video recordist: Konrad Gutkowski/Julian Blaschke


21.2 MB
2 min 0 s
2 (Stereo)
Sample rate:
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Bit depth:
44.1 kHz
1411 kb/s
16 bit
87,4 dB

Recorded on March 27, 2014
Windmühlenmesser Robert Herder
Solingen, GERMANY
Creative Commons License