Are these the nuts you are looking for? From what I can determine the shaft may be a metric M24 x 1.0 (bolt thread dia. 24mm x 1.0 pitch). The nuts seem to be 6mm thick (two are 12mm thick) and fit a 33mm wrench. Good luck in finding these.
It is not metric all threads on Alpines & tigers are imperial UNF & UNC in most cases