I bought the KD 2190 tool and made great 3/16" double flares as I finish my 13" C4 upgrade. My 1/4" attempts are lousy, usually having an oval hole after the first step. I assume this is because the end is not perfectly square but I don't know what else to try. I have used a hacksaw and chop saw, carefully deburred inside/out and had what looked to me to be a good, square end. This is driving me crazy since I am on the last piece.

Suggestions welcomed. Thanks.

I don't want to sound patronizing, but what about a tubing cutter ? You can get either a regular or "mini" sized unit at Home Depot or similar for about $10.

They automatically make a square cut due to the rollers that saddle the tubing, keeping the cutter wheel perpendicular to the tubing.

my .02

Not patronizing at all. I also have used a tube cutter. Keep any/all ideas coming.

I was having a bad time double flaring brake lines recently. I posted a question and had many replies. Maybe search double flare and see the answers. In the end, I found that the clamp on my flare tool was not absolutely level on both sides. It was leaning a tiny bit once I started cranking it down. So I put a feeler gauge under one leg of the clamp, to make it absolutely perpendicular to the base that was holding the pipe, and that did the trick. I think I only used about .10 thou but that might be all that it takes.

Yup. I'm blind from reading posts! I'm going to try that tonight. I think it's an alignment issue too. There's a bit of play in the tool which could stack up. Was your tool the KD 2190?

I have used several different flaring tools, and the only one that always would stay straight was a MAC (I think) which had bevels inside the whatchamacallit (the U-shaped part). When you tighten it up, the bevels will make full contact with the sides of the clamp, and it seems like this makes it stay more straight than other tools. You should also deburr the inside of the tube after cutting it (with a tube cutter, as already mentioned), so the mandrel goes in perfectly centered.

I messed up my first couple attempts by having too much tubing above the clamp. I started using the thickness of the back of the mandrel as a insertion depth guide and never had another issue. FWIW, I use a Snap-on set.

I use my (hand-me-down) Dad's kit that he bought around 1950. It's very similar to the one's I've seen recently.

The trick to this kit is that the mandrels have a built in guage to tell you how much tubing is to stick up from the "anvil". I messed up at least 1/2 dozen ends until I bit the bullet and did another dozen on scrap pieces to learn the "peculiarities" of this tool.

BTW - Step One - put the fitting on the tube before you start! graemlins/clonk.gif graemlins/clonk.gif graemlins/clonk.gif :D

Are the lines steel or stainless?
I tried to double flare stainless steel and it gave me fits. I called The Right Stuff, where I got the lines and they told me I wouldn't be able to do them my self. I sent them back and they did them for me. graemlins/hurray.gif

Steel, not stainless. I just put more time into the prep ensuring the end was really squared off and they are coming out nice.