"Bob La Londe" wrote in message news Deep (50.8mm) threading M36-4. What's your first choice to do the job.
Can't be turned. Can be milled.

I have some tiny little micro boring bars I use for deep thread milling
small threads, but a 4mm pitch needs a huge tooth... and of course the
reach to do the job.

Not my project. Operator would prefer some form of thread milling. The
work piece was not described.


That project is going to require some pricey tooling.
Best Regards
Tom.