2003 90hp Ficht steering arm thread query

[Chip1966]

Hi,
Could someone please tell me what size and type thread is in the steering arm? Here in the UK we only use metric these days and therefore i haven't got a selection of bolts to check it. The thread taps I borrowed didn't fit and the thread gauge is too wide to go into the hole. Please see the attached photo of the arm and thread in question.
Thanks for any help that you can give.
Chip Wilson
Southampton
UK

[boats.net]

It's a 3/8-24 hole.

[Chip1966]

Really sorry, I've just realised that i forgot to reply and thank you. You were of course correct.. 3/8 UNF
:-)