Rough Threads Single Point Threading

[Sailplane Driver]

I don't know, to me the 2 threads to the left look boogered.
Same problem?

First two threads on the left were "boogered" due to my not completely engaging the half nut.

 

[Sailplane Driver]

Another example of why I try to discourage purchase of inserts on eBay unless you have a way of verifying authenticity. Full packs especially should raise a red flag. Those "Mitsubishi MMT11ER AG60" you mentioned you purchased on eBay are not made by Mitsubishi as best I can tell. According to Mitsubishi published information, they do not make an "11" sized (1/4" I.C.) AG60 insert for external threading.

Glad you got your threading accomplished.

I've learned my lesson.