Two steps forward and one back.

Hoping someone has seen this before and has the answer. While getting ready to run lines for the new Carb setup I'm replacing the in tank screen and blocking off the small FI return line. Seems the aluminum fitting threaded onto the large tank flange has decided to leave half it's threaded material imbedded into the male threaded gas tank fitting. Need to clean out the trapped material. Anyone have the thread particulars so I can locate a die to chase the threads or is there another way. Also looks like I'll need a female nut special for this case. Where to go for this item ??

M18 * 1.0
Nissan pick up spindle nut.
Dorman 615-087 5 pk.

If we ever run across one another in person remind me that I owe you a Beer !!! This worked wonders with the threads now restored and most of the aluminum removed. Now off to find the new replacement Special fitting nut I need for this application.