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Guaranteeing quality

Consistently high quality is the top priority for Lederer. This applies to the quality of both products and services.

All parts are subjected to a systematic quality analysis and assessment. Physical and chemical properties are examined with modern measuring instruments and compared with the desired properties.

Within individual agreements with the customer, it is even possible to carry out a 100% inspection, i.e. each individual part is subjected to an inspection before it goes from the warehouse to the shipping department. In this way, even exceptional and the very highest quality requirements can be met.

The employees in Lederer's own testing department have modern tools at their disposal: from mechanical measuring instruments such as micrometers, depth gauges and plug gauges to hardness testing equipment and projectors to the latest RFA and spectral analysis equipment as well as 3D rotation measuring devices. All measurement and test results are documented in software specially developed for this purpose and made available on request.

The criteria that can be examined include the following:

  • Dimensions (manually and with 3D rotation measurement system)
  • Threads and breaking torques
  • Hardness in accordance with Rockwell (HRC) and Vickers (HV)
  • Material types
  • Coatings (RFA)

In addition to its QA testing department, Lederer GmbH has its own testing laboratory accredited in accordance with ISO/IEC 17025. In this lab, even more detailed investigations can be carried out and certificates issued.

The Lederer testing laboratory can carry out the following activities:

  • Measurements (manual and fully automatic)
  • Thread tests (including gauge accuracy, coefficients of friction, torsion tests)
  • Material analyzes and microscopic structure investigations
  • Tensile tests for full-size bolts and screws
  • Tensile tests under wedge loading
  • Proof load test for nuts and breaking torque test
  • Hardness test for core and surface hardness
  • Notched-bar impact bending test at lower (down to -110° C) and higher temperatures
  • Drill speed test for self drilling screws
  • Coating thickness test and Roughness measurements
  • Salt spray tests
  • Miscellaneous manual tests


In many branches of industry, moreover, fasteners with TÜV (German technical testing institute) approval are required. Lederer is one of the few suppliers whose product assortment depth now leaves hardly a wish in this area unfulfilled. The articles in question are given the designation „TÜV approved in accordance with AD-W7/2“ and the material specification „A 2-70 / A 4-70“ in the Lederer catalogue.

The following test certificates can be issued: