billh wrote:
You don't need the screws for regular turning since the force of the cutting
tightens the chuck on the thread. The number of threads contacting is
plenty. You should use the screws when you are cutting with the lathe in
reverse. Light sanding should be OK in reverse without the screws but as a
precaution they are a good idea when doing anything in reverse.
The screws do not come with the chuck and they are metric M8 setscrews. I
think the M8 specifies the thread pitch as well as the diameter but am not
100% positive about that.

Nope ... there's a coarse (1.25mm pitch) and a fine (1.0mm pitch)
version of M8 and upwards. See

http://www.metrication.com/engineering/threads.htm

That having been said, I'd bet on it being the fine version.
--
Alun Saunders