  The use of chirally rotated boundary conditions provides a formulation of the
Schroedinger functional that is compatible with automatic O(a)-improvement of
Wilson fermions in the bulk. The elimination of bulk O(a) terms requires the
non-perturbative tuning of the critical mass and one additional boundary
counterterm. We present the results of such a tuning in the quenched
approximation at three values of the renormalised gauge coupling and for a
range of lattice spacings.
