For each well approximable irrational θ, we provide an explicit rank-one construction of the e 2πiθ -rotation R θ on the circle T. This solves "almost surely" a problem by del Junco. For every irrational θ, we construct explicitly a rank-one transformation with an eigenvalue e 2πiθ . For every irrational θ, two infinite σ-finite invariant measures µ θ and µ ′ θ on T are constructed explicitly such that (T, µ θ , R θ ) is rigid and of rank one and (T, µ ′ θ , R θ ) is of zero type and of rank one. The centralizer of the latter system consists of just the powers of R θ . Some versions of the aforementioned results are proved under an extra condition on boundedness of the sequence of cuts in the rank-one construction.