Straightening has to be carried out in order to ensure the straightness of a shaft. as distortions exceed the tolerance limit. Since the straightening load is typically large enough to produce plastic and residual deformation. repeated straightening loading cycles are very likely to induce cracks or fractures on the case-hardened shaft surface. https://lecoureures.shop/product-category/ski-de-fond-enfant-fixations-skate/