Item Durability

[Chez]

How can I make durability of a leather helmet for example 200? Im trying to make emerald armor and idk what to do.
Script:
on load:
set {_emerald_helmet} to leather helmet named "&fEmerald Helmet"
dye {_emerald_helmet} light green
register new shaped recipe for {_emerald_helmet} using emerald, emerald, emerald, emerald, air, emerald, air, air, air with id "emerald_helmet"

 

[Minecoll_YT]

As far as I know, you cannot change the default minecraft durability. But you could make your own durability system using lore/metadata and the "on item damage" event