Do you have access to some very fine watchmakers needle files - you may be able to remove some of the damaged parts of the thread so as to get the nut...

Is the thread stripped? It is difficult to discern from your photograph but it looks like that might have happened if you cross threaded the nut. Y...

Hi Iab, Silly question, but is the ER11 collet properly mounted in the nut - it should have "clicked" as you pressed it in. You have to get it orie...

Thank you Ubo but it's missing 🙁