Bending brake and fuel lines is actually one of my favorite things to do on a car or truck. (I know...I'm sick)
First...you MUST use a double flare, 45-degree. You can not do a single flare, period. All automotive fittings are 45-degree double flare. A single flare won't seat.
Second, while I know you've spent a decent amount of money, there is a HUGE difference in the quality of the tools out there. 15 years ago, when I was 17, I ponied up the $$ for a Snap-on tubing cutting and flaring kit. It was $93, and the best money I've spent in the garage to date. This kit is responsible for my good results.
One of the key compnents is a high quality tubing cutter. I had to replace mine because I lost it, and it was around $45. I tried a couple from Sears, NAPA, etc. before biting the bullet. The cutter is the difference between a good job and a pain in the butt.
The flare tools themselves are also high quality, and they'll make a difference as well. Between a poor cutter that doesn't cut square, and a holder that lets the tubing slip as you form the flare, you'll end up with cracked, lopsided or otherwise messed up flares.
The Snap-on kit I have is now up to $120 (not bad inflation for 15 years), and is available on their website. I don't have the link, but it's in a red box, has a silver tubing cutter, and polished holder and flare tool, along with 5 flare dies.
A couple years ago I added a couple dollar-bin small files to the box...one round and pointed, one flat, to deburr the cuts. I never had a problem with it before, but I figured it couldn't hurt.
I've made lines for a '56 Chevy, '54 Buick, '69 Camaro, '57 Chevy, '62 Suburban, a couple of late-model Dakotas, and more, and the only problem I've EVER had making a flare is forgetting to put the nut on before the flare. That'll kill you every time!
Don't get discouraged. Invest in the high-quality tools, and this will become a job you'll actually enjoy. Step-by-step instructions are pasted inside the lid of the Snap-on box...follow them, and you can't go wrong.
-Brad
