In 2023, the use of hardwood for construction remains uncommon, despite the significant percentage found in European forests. France, in particular, possesses ample quantities of oak (mainly Quercus petraea / Quercus robur) that are generally considered of low quality due to high flexuosity, small diameter, and/or numerous knots. Consequently, it is primarily relegated to firewood or slushing applications. Its potential is underestimated due to the absence of strength grading machines capable of ensuring its mechanical properties according to European Standards. This dataset encompasses the results of destructive testing conducted on 924 second-quality oak boards required for strength grading in compliance with European standards EN 14081-1 (2016) and EN 14081-2 (2018). Emphasis has been placed on complete traceability and representativeness, with the boards originating from four different regions in France and 108 distinct trees. The boards vary in cross-sections ranging from 70x21mm² to 140x35mm² and were subjected to tension testing following the EN 408 (2012) standard. This dataset can contribute to the development of standards for hardwood strength classes under tensile loading, as well as engineered hardwood products such as Cross-Laminated Timber (CLT) and Glued Laminated Timber (Glulam). In conjunction with grading machine data, it can facilitate the proposal of oak timber strength grading methods.