I just popped open the old Carroll Smith "Nuts, Bolts, Fasteners and Plumbing handbook".

Looks like Carrol Smith recommends 37 degree AN single flares for brake lines. But, they need to be made with a real 37 degree flaring tool.

A quote from his book:

"The standard American double flare is an SAE 45 degree flare and is not suitable for use with the AN fittings which are 37 degree cones. I have spoken with a number of experienced and even respected mechanics who, while they are aware of this difference, ignore it. These people fell that, by graunching down hard enough on the coupling nut, they can seal the assembly. These people are fools!"


Looks like this is what you need for adaptors:
http://www.summitracing.com/parts/EAR-561803ERL/

And one of these for the flares (not cheap):
http://www.toolbarn.com/ridgid-41162.html

JonArmstrong Wrote:
-------------------------------------------------------
> I just popped open the old Carroll Smith "Nuts,
> Bolts, Fasteners and Plumbing handbook".
>
> Looks like Carrol Smith recommends 37 degree AN
> single flares for brake lines. But, they need to
> be made with a real 37 degree flaring tool.
>
> A quote from his book:
>
> "The standard American double flare is an SAE 45
> degree flare and is not suitable for use with the
> AN fittings which are 37 degree cones. I have
> spoken with a number of experienced and even
> respected mechanics who, while they are aware of
> this difference, ignore it. These people fell
> that, by graunching down hard enough on the
> coupling nut, they can seal the assembly. These
> people are fools!"
>
>
> Looks like this is what you need for adaptors:
>
>
> And one of these for the flares (not cheap):
>

I would expect any person able to join and post on this forum would be bright enough not to mix a double flare, or any flare other then an AN with an AN fitting. I guess i have to high of expectations for the members here.

Brake lines are double flare because the tube nut runs directly on the outside of the flare. (Technically, they are also only good once) There's a twisting grinding action going on in there.

AN tube nuts have a separate sleeve. The sleeve bears on the outside of the flare without torquing on the flare. A much better, more reliable, and more reusable method of sealing.

A 37deg flare tool isn't that much more expensive than a double-flare tool that works worth a damn.

I know that steel is supposed to be used for brakes, but every drag car I've seen that was done in all-AN has used aluminum tees and bulkheads. Scary!

---

Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Just to add a little story to this, best friend was installing a new cook top the other night and we smelled gas, come to find out the flex line he had installed had jic 37 degree fittings on it but the company failed to use seamless tubing. so here we see the importance of using quality tube with your 37 degree stuff. Once we pulled it all apart you could clearly see the seam in the fared end of the hose, along with a spot that wasnt contacting the face on the male end.

token-negro Wrote:

> I would expect any person able to join and post on
> this forum would be bright enough not to mix a
> double flare, or any flare other then an AN with
> an AN fitting.

Advice such as this seems to contradict your hypothesis:


John Vanlandingham Wrote:
>You can completely safely flare the tube to SAE 45 and use it on a AN/JIC 37.5 in >3/16 and even 3/8

token-negro Wrote:
-
> I would expect any person able to join and post on
> this forum would be bright enough not to mix a
> double flare, or any flare other then an AN with
> an AN fitting. I guess i have to high of
> expectations for the members here.
>
>
>
I would expect any person here to consider what they do for work, and what people within the trades we are speaking of do and say. I would never had even tired this had not more than a couple of people in the hyraulic supply and race car build business said "Consider the angle difference between 37.5 degrees and 45 degrees on a 3/16th flare. It differs by mere ten thousanths of an inch--well less than the average person can be certain that they just did on their flare."

And actual experience has proven them right.
Dozens and dozens and dozens of times over.
Reality MUST count in the end more than a book by an fellow famous for extreme pedantry who works primarily in areas of limitless budgets, and idealised situations.

Of course on larger sizes it would never work.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Ok so this works ONLY on 3/16 3an stuff and only with SAE double flare? So the odds are this worked for someone who had ZERO knowledge of the thou they are off and it works thus they think they can do this on all AN fittings. Just the way people are. Much safer to just say it does not work and leave the anomoly to the smart guys then.

It's always something, either it works or its right? Ill take right over well it works fine.



Edited 1 time(s). Last edit at 12/16/2009 09:59PM by token-negro.

BTW - look around the net, you can find 37 degree flaring tools (quality ones that usually go for $100+) in the $25-$30 range. The one I found was brand new, never been used.

My hydraulic guy has also indicated that in certain sizes 45 and 37 degree are compatible.

Lucky for me, since I used to work on aircraft, have a 37 degree flare tool kicking around in my tool box.

-----------------------------------------
>
>
> I would expect any person able to join and post on
> this forum would be bright enough not to mix a
> double flare, or any flare other then an AN with
> an AN fitting. I guess i have to high of
> expectations for the members here.
>
>
>

So many wisecracks, so little time...

vbares Wrote:
-------------------------------------------------------
> BTW - look around the net, you can find 37 degree
> flaring tools (quality ones that usually go for
> $100+) in the $25-$30 range. The one I found was
> brand new, never been used.
>
> My hydraulic guy has also indicated that in
> certain sizes 45 and 37 degree are compatible.


How about sharing some of your awesome deal searching skills with some links...

see there..phlat65 will *give* you one :p

Here's where I found mine:
http://connecticut.backpage.com/ToolsForSale/_25_imperial_eastman_37_and_45_degree_tube_flaring_tool_new_1_860_668_7266/classifieds/ViewAd?oid=2581075

I'm sure there are other sources - the mainstream crapbay ain't gonna cut it though. CL is ok, use www.searchtempest.com for easier searching...

I have seen 45 double flare matched to A/N fittings and inevitably they leak. the stainless line will gouge the fitting and after service the seal is shot and leaks.

---

Boost early and Boost often

Beating a dead horse here, I know.

Found the SAE flare spec online: http://mecholsky.mse.ufl.edu/EMA4714/Flare%20Tube%20Specifications.pdf

Looks like the diameter difference of the flare between a 45 degree single flare and a 37 degree single flare is indeed pretty small as John has theorized.

-for 3/16" line, there is a 0.026" difference in diameter
-for 1/4" line, there is a 0.030" difference in diameter.

So, using a 45 degree flare tool for a 37 degree fitting, the diameter would have to be crushed by this amount when the tube was mated to the fitting for the first time.

JonArmstrong Wrote:
-------------------------------------------------------
> Beating a dead horse here, I know.
>
> Found the SAE flare spec online:
>
> Looks like the diameter difference of the flare
> between a 45 degree single flare and a 37 degree
> single flare is indeed pretty small as John has
> theorized.
>
> -for 3/16" line, there is a 0.026" difference in
> diameter
> -for 1/4" line, there is a 0.030" difference in
> diameter.
>
> So, using a 45 degree flare tool for a 37 degree
> fitting, the diameter would have to be crushed by
> this amount when the tube was mated to the fitting
> for the first time.

Thats is all true but what I feel is the issue is when we mix and match aluminum and steel fittings. If you are using stainless tube, and alum tube nuts on an alum bulkhead that extra torque as little as it is now possibly groves up the mating face on your alum fitting. If you are in a pinch with all steel or all alum tube, tube ends, fittings etc then it should work right? THe question is if u cant borrow or afford a 37 Degree flare tool to just do the whole thing right.