My Pine staircase has been creaking for a few years now. The treads and
risers seem to be coming un-glued from the side faces. I intend to
re-glue them all and then tension the side faces together. I'd like to
used a decorative Coach bolt on the outside and threaded rod. Does
anyone know of a turn-buckle with a left and right handed thread
suitable for M8 threaded rod.

TIA - Chris.