I think Martin Barrett in S. Australia will have this info as he has made a number of these items - from scratch! Try martinstuart.barrett[at]gmail.com
Dick Morbey PA/PB 0743 Nr. Henley-on-Thames, Oxon, UK
Cees, one of the gears is with 23 teeth, the other 54 teeth. Ratio 54 / 23 = 2,3478 and Modul 0,5. I repaired one long time ago, from this i found a receipt.