Help with brake fitting sizes
 

Any one have an idea about brake fitting sizes on a set of Lincoln calipers on my ford 9" rear. This is the brake line fitting. I thought they were 7/16 24 and then thought they were 7/16 20. No dice. 7/16 is the right diameter, but the threads won't start. It is to big to be a 10mm 1.5...banjo fitting..

Any thoughts? Maybe they are NPT....

Darren