Threading

Hi

I need to make some 1/2" whitworth studs, what is the best way to do this on a lathe?

In the past I have cut the thread almost to size with a 55 degree HSS tool then finished it off with a die.

Last time I used the tool I broke it so I need to get a new one but what I really want is an indexable type tool, I've looked through a few suppliers on the web but I can't find any that sell this type of tool.

Does anyone know of somewhere that sells indexable type threading tools.

Thanks

Liam