Tips for flaring for AN fittings.

[Samckitt]

Is there any tips, or instructions anywhere for doing this to make sure I don't have any leaks?

Or is it as simple as cutting the tubing, flaring it & good to go?

Thanks,

[parsonsj]

These may be obvious, so apologies in advance if you already knew this:

1. If using stainless, watch for work hardening. Don't use a tubing cutter, use a saw of some sort that generates chips. I use a bandsaw.
2. Get the cut square. I use a belt sander to get it "just so".
3. Use grease on the expanding die, so there is less tendancy for the tube to slide away rather than expand.
4. The flare should be big enough to just allow the nut to slip over it. It is a common mistake to not make the flare "flared" enough, which leads to leaks.
5. Debur the cut. I use a chamfer cutter in a drill for the inside, and the belt sander or a file for the outside. Don't take too much material off ... remember this exact area is where the metal gets stretched the most.
6. Don't forget to put the sleeve and nut on the tube before flaring! Or you'll be very disappointed.

jp

[Marktat]

Don't forget AN flares need to be 37 degrees, as a opposed to standard automotive 45 degrees.

You probably know this but just wanted to be sure.

[Samckitt]

I have a Ridgid 37 degree flaring too. This thing works great. I highly recommend it if anyone is debating on which one to get. I got it on Ebay.

Can I use a tubing cutter if I am not using stainless?

What about deburring it after cutting it? Need to do it or not?

Thanks

[parsonsj]

If you're just using steel tubing, then work hardening is less of a problem. Perhaps a tubing cutter will be ok, but I've never done it that way. The advantage of the tubing cutter is square cuts, so it may work better than cut and sand for steel tube.

Good question about de-burring. I use an 82 degree chamfer cutter in a drill to debur the inside of the tube, and a quick pass on my belt sander to get rid of the burrs on the outside. Then I blow the tubes clean with compressed air before flaring. I added that info to my post above.

jp

[silver69camaro]

We use stainless tubing from Classic Tube, and we never have any problems with work hardening. We just use it like regular steel tube.

[parsonsj]

We use stainless tubing from Classic Tube, and we never have any problems with work hardening. We just use it like regular steel tube.

Matt, can you define what you mean by "use"? Are you saying you cut stainless tube with tubing cutters?

jp

[Jim Nilsen]

On the tubing I got from Classic Tube I was able to use tubing cutters with no problems that I can see. I am using a Ridgid flairing tool which is a lot better than the cheaper tools.
Maybe when I do the 3/16 tubes it will be easier and better to cut it but the 3/8 and 1/2 has been very easy to work with.

Jim Nilsen

[parsonsj]

On the tubing I got from Classic Tube I was able to use tubing cutters with no problems that I can see

Huh. Good to know, because one can sure get a better, squarer cut with a tubing cutter.

jp

[BonzoHansen]

Never used SS lines, but for steel or alminum lines, I've had no problems with a tubing cutter. I got a deburring tool form home depot for the inside and I use emory paper on the outside, maybe a slight bevel on the outside on the grinding wheel. I use 3 in 1 or other oil on the tube when i am flaring it. No issues with 45* double flares.

Yes, put the nuts on first....

[Kenova]

I've only AN flared aluminum, but the Rigid tool is just the Cat's A$$.

4. The flare should be big enough to just allow the nut to slip over it. It is a common mistake to not make the flare "flared" enough, which leads to leaks.

I found it almost easier to make the flare a little too big and then trim it down with a fine file. With enough practice a person could easily make the flare the perfect size each time.

6. Don't forget to put the sleeve and nut on the tube before flaring! Or you'll be very disappointed.
jp

Forgetting to put the nut and sleeve on before flaring will produce a perfect flare every time. At least that has been my experience.
Ken

[Samckitt]

Is there a certain type of steel line that should be used? Or do all of them have the seam where it is formed together? Any problems with it sealing on this seam in the flared area?

[Twin_Turbo]

you can only single flare seamless tubing, no n seamless has to be double flared to turn the smooth otuside inwards to create a perfect sealing surface.

I've double flared alumium, steel and single flared seamless stainless, all it takes is a high quality flaring tool.

Also, never use a tubing cutter on stainless lines, you will work harden the cut area and destroy the flaring cone in a hurry.

[silver69camaro]

Also, never use a tubing cutter on stainless lines, you will work harden the cut area and destroy the flaring cone in a hurry.

Read above. Stainless lines from Classic Tube do not have this problem. Others may be OK too, but I've only used it from Classic and Williams Oil and Filter Service in Tacoma, WA. Both work great with standard tubing cutters and double flare tools.

I'm going to go out on a limb and say this...45* flares do not leak on 37* fittings. Many, many pro builders use 45* on AN fittings...I know, I know, you shouldn't do it. But it does work.

I'm putting my flamesuit on as we speak.

[Samckitt]

So what I am hearing is with a seamed tubing, I will have leaking problems with a single flare 37 degree flaring tool....? It is a good quality flaring tool, it is a ridgid brand tool.
Thanks.

[BonzoHansen]

So what I am hearing is with a seamed tubing, I will have leaking problems with a single flare 37 degree flaring tool....? It is a good quality flaring tool, it is a ridgid brand tool.
Thanks.

It is not the tool. It is the seam.

[Twin_Turbo]

exactly.

Sam, does your tool do double flares? Is it capable of stainless? Most aren't. A tool capable of doing stainless is very expensive, like the imperial 400F, I have 2 papco rotomasters and they do an awesome job, however they were not cheap.

[parsonsj]

Stainless lines from Classic Tube do not have this problem <edit: we're talking about work hardening>. Others may be OK too, but I've only used it from Classic and Williams Oil and Filter Service in Tacoma, WA. Both work great with standard tubing cutters and double flare tools.

Let's be careful, please. I understand that many people are successful using tubing cutters on stainless steel tube. No leaks, no muss, no fuss. That's cool, and a useful data point.

However, it is true that austenitic (304, 316, 18/8, etc.) stainless steel as a material (no matter the supplier) work hardens much more readily than mild steel. That's a property of the material itself, not the supplier. I'm guessing the ss tube that has the best luck is thoroughly annealed (sometimes advertised as "triple annealed") prior to cutting.

The reason I mentioned cutting ss tube with something that generates chips is to enhance the possibility that the cutting tool will get under the work hardened surface as it cuts, leaving a still annealed end available for flaring. Using a tubing cutter is obviously less desirable from the viewpoint of having the most ductile material possible for the flaring operation.

On the other hand, it could be argued that the advantage of a perfect 90 degree cut (as is usually achieved with a tubing cutter) is worth the work hardening disadvantage.

Hope that makes sense.

jp

[Twin_Turbo]

I have no problem getting the end perfectly straight, I use the clamping blocks from the flaring tool, insert the pipe and check if it's completely flush, I file to correct. Works every time.

[Samckitt]

Twin-turbo - No the tool cannot make double or inverted flares. Not sure if it will do stainless, I don't see why not. You say a tool that does stainless is very expensive, what do you consider expensive?