TPI in metric? And a few other leadscrew confusions for newbie

[glynster]

Excellent, I think I am finally understanding, so to confirm then this product from Moore International is 10mm diameter will advance by 12mm with every turn (approx half an inch)?...

http://www.mooreinternational.co.uk/...0-12screw.html

Does the nut also have to match the 12mm pitch?

[Neale]

Yes, that's a 12mm effective pitch (=lead) 4-start thread. And yes, you need the matching nut. There appears to be a dropdown box to choose Delrin or bronze for that.