Hi All, I've got a Familia 320GT and have just replaced the gas bottle, any guidance on how much to tighten the nut, I'm worried I'll over tighten and knacker the thread?

Hi welly1,
I guess it’s a propane bottle, with an all-brass bullnose since you talk about the Nut.
The short answer is “the minimum force to make a seal”. You’re more likely to damage the surface of the bullnose or seat of the valve than the thread.
Accessory shops sell cylinder spanner’s with a short handle, maybe 120-150 mm long; these are intended so you don’t overtighten.
(You can buy cans of leak detector to check that the seal is good.)
Hope this helps.

Thanks for the note, I'm reassured that I wont cause damage by overtightening, the first time I connected it I could slightly smell gas but now I know I can tighten more!