If you use the proper fittings, won't see crap like this: I found a source for those fittings. Well, two, actually. The first is Eastwood.
Steel Line Tubing Kits- 25 Feet with Assorted Fittings
Item #49053 brake lines The Eastwood kit includes 25 feet of brake line, also.
More than likely, Eastwood sources their fitting from the original manufacturer, which I believe is S.U.R. & R Auto.
SUR&R appears to make the brake tube bending pliers and Deluxe Flaring Tool that Eastwood sells. It's just rebranded.
http://www.surrauto.com
S.U.R. & R. Brakes The SUR&R kit comes with more than anyone would need for a whole car (except for enough of the regular 3/8-24" threaded fittings, perhaps. But they also sell the fittings in 4 packs if you don't want to buy a whole kit with fittings you don't need.
SUR&R also has a fitting that has a larger HEX area, but still fits the standard small flare joints. It allows you to use a bigger wrench and makes them less likely to strip when you are swapping out parts!
Edit: 05April2017
I found another supplier of the oversized fittings: AGS
They sell them in bags of 10, cards of 5, or individually.
All tubing on our 60s and 70s Lincolns is 3/16" for brakes. A standard 3/16" tube fitting has 3/18-24 thread. The sizes one MIGHT need are
- 7/16-24, AGS # BLF-11 (10 pack)
- 1/2-20: AGS # BLF-41 (10 pk), BLF-41C-5 (5 pk)
- 9/16-18: AGS # BLF-42 (10 pk), BLF-42C-5 (5 pkk)
The fittings can also be found at other sellers and on Ebay, etc. They're not too expensive, but it beats using adapters.