Star-lock washer.....

Hi guys =)

may be abit of a tough one, just done the gear actuator fix on my meglio, bored the nylon bush out and it now feels like a brand new gearbox =), however the stacklock washer on the end of the shaft didnt look in the best condition even before i had to molest it! does anybody know the size of the starlock washer i will need just in case i need to replace it..........or it falls off haha

TIA =)