Thread mill question

[Froneck]

I have never used thread mills and don't intend to mill threads. I'm wondering if internal thread mill have a lead or are they rows of Vees that when used on CNC can create internal threads. If there is no lead I'm thinking of using them to cut serrations.

 

[guythatbrews]

No lead...

 

[Froneck]

Thanks Guythatbrews!