Torque Application Tools
according DIN EN ISO 6789
Direct reading beam type torque wrenches

Denominated as „torque wrenches“ are manually operated tightening tools by which a defined tightening force (torque) can be applied to joint elements like bolts or nuts. According to DIN EN ISO 6789 torque tightening tools are differed into indicating (type I) or releasing (type II) models.

Type I indicates the torque value by a mechanical scale, a dial gauge or an electronic display (“measuring wrench”):

  • Class A: with torsion bar or beam lever
  • Class B: with scale, dial or digital display
  • Class C: with electronic measuring
  • Class D: screwdriver with scale, dial or digital display
  • Class E: screwdriver with electronic measuring

Type II is to be preset to a certain set point activating a signal as soon as the set value is achieved (“signaling wrench”):

  • Class A: adjustable, with scale/digital display
  • Class B: preset
  • Class C: adjustable, without scale
  • Class D: screwdriver, adjustable, with scale or digital display
  • Class E: screwdriver, preset
  • Class F: screwdriver, adjustable, without scale
  • Class G: with beam lever, adjustable, with scale

Specified Measuring Range

The requirements and verification procederes of the DIN EN ISO 6789 are valid for a measuring range from 20% to 100% of the rated capacity (maximum value). The effective span of a torque tool may differently begin lower.

Allowed tolerance type I

  • Class A, D: ± 6%
  • Class B, C E: upto 10 Nm ± 6%, beyond ± 4%

Allowed tolerance type II

  • Class A, B, C: upto 10 Nm ± 6%, beyond ± 4%
  • Class D, E, F, G: ± 6%

Required marking

According to DIN EN ISO 6789 the manual torque tools delivered by us are durable and easily readable marked with at least following information:

  • Rated capacity (maximum torque)
  • Unit
  • Direction (if not bi-directional applicable)
  • Manufacturer or brand
  • Serial number (as far as calibration cert. is included)