|
So if you are measuring the inside of the hole, the inside diameter of the thread, it seems too small for the ID of a 12mm thread. Have measured mine and the ID is approx 10.2 mm, my handbook gives a tapping drill size of 10.2 for a 12 mm thread.
The 8.55 mm that you measured is close to the tapping drill ( inside diameter ) of a 10 mm thread. How old is your mount, maybe Skywatcher have changed the thread size recently. Would be handy if some other recent owners of the mount could chime in with some info to enlighten us.
|