cyrano-stealth shaft thread size??

[vti-chris]

Hi,
I have a sporasub stealth 85cm gun and i want to use the harmonic shaft that comes with it with a 3 tip spear head.
The one i got has bigger female threads than the shaft to screw in.
So i got an adaptor and the adaptor screws on the tip but not on the shaft cause is too small.
I need an in between thread (between the tips threads and the adaptors threads) but don't know the mm of the female thread.

[dave]

The thread on the shaft is M7x1
cheers
dave
www.spearo.co.uk