Sorry I don't understand the problem. I learned to flare on A/C equipment with single flares about 50 years ago. I still use one of those Chinese? kits in the red plastic boxes that are on every import tool table at the shows. I used the same kit at my brake shop. I've done a bunch over the years. I can't remember the last time that I had to redo a double flare. Am I that good? I don't think so. I personally I think that some of you guys are soooo paranoid about a new process that you are not used to that you talk yourself into having a problem. A magnifying glass? really? It sounds like you want to have a problem and keep looking until you can find one. I don't really want to insult anyone but I have to get it off my chest. Before you get all pissed off and start cussing me. Just laugh at me for being an old school old fool. All the technocrats with their expensive tool are much smarted than me. For the new guys that are still a little leery, get a kit and practice. It ain't rocket science. At one time I would fall on my ass when I first tried to walk. I kept at it and I finally got the concept. I even could run a little. Now not so much. C,mon....it's not that hard!
A few times over the years I have come across a piece of tube that will not flare properly. I have seen the occasional case where one or more components on the flaring tool is worn out or improperly made. I have seen a few cases where a little lube on the tube end or die helps. If you use anything other than brake fluid as a lube make sure to thoroughly clean the line before using it. The preceding exceptions aside, most flaring problems are due to operator error.
Been making my own lines for over thirty years both with the standard imperial, and as of the last four years, the Mastercool hydraulic set (mainly for bubble flares, but it's easier on your hands). What I've found, is poorly made or worn line clamps tend to spread and create the gap. Even the hydraulic unit tends to spread slightly (probably due to the fact it's easy to use too much pressure) and this leaves two small ridges on the back side of the flare that the flare nut has to flatten to put correct pressure on the flare to seal. This is mostly a problem with smaller (3/16) than anything else. I just file the two small ridges flat, and I've never has a problem. It's a habit I got into years back...
isn't 37deg the same as JIC? i have flared many a brake, trans, and fuel line. start out with some aluminum and practice with that. a crack on a double flare is not a death sentence, hook it up and put some pressure on it... i'm guessing if your opposed to a JIC fitting like -3 or -4 your probably not running a modern power brake system either. if you scrutinize each flare to that degree and reject 25% of your flares 50% of your lines wil be rejected or not exactly how you wanted it when you first cut it.
Ditto, thought getting the tool from the snap-on guy was the answer but still errors occur, even in the vise mounted clamp. Still beats a 40 mile round trip to get a piece that isn't the perfect leingth. Keep some store bought at home plus some coils & assorted nuts, couplings.
i was taught to debur inside and file slight 45 degree on outside. done hundreds of lines on the bench and on the car (sometimes in some hard to get areas). only had to redo a few. cheesy line clamps that don't tighten around line are the norm, leaving two ridges, top and bottom, i second the c-clamp method but it has to be placed strategically as your flaring tool grips where you want your c-clamp. i buy the green line by the roll. less fittings= less leaks.
thinking i had the brake flaring thing all figured out on the last project, i started flaring lines with confidence only to see my flares were off center. after inspection i found that the tubing was off. the wall was thicker on one side making it impossible to center a flare
biggest issue with flaring is line prep. cut the line, ream it, file it flat [couple scuff's usually gets it], and have at it. in my experience, line prep is the key. seen many a shitty flare due to not reaming and filing the line before flaring. been a wrench for 25 years, and have flared a ton of brake line, for me, prep is the key.
I bought one of these on ebay a few years back brand new for $150. I have never had an issue and they make a perfect flare every time. Well worth the money. http://cgi.ebay.com/ebaymotors/Mast...t=Motors_Automotive_Tools&hash=item2562934c24
I'd just echo most of the rest of the posts, good line prep, square end on the tubing, file, or chamfer the inside and outside very lightly to preven stress cracks from forming. I picked up a carbide chamfering tool from McMaster to help clean up the inside of a tubing-cut line. Helps a LOT! Looks like a deburring tool with a conical cutter on the end. Also a touch of oil on the tool helps. Buying a good tool is the biggest help, though. I finally spring for a RIGID and it's the best I've ever used. Saving for a hydraulic one eventually.
It amazes me when I read about $300 tools to do something so basic.Just like what was said before me ,I clean the burr out of the line with a drill bit,square if required with a file,anti seize on the end and flare. Some people want to overflare . I think I have done about a thousand of these over the years with a cheap garage sale import kit. As far as looking at them with a magnifying glass, come on folks. I love going to someones garage and they tell me they don't have enough money to finish their car and they have thousands of dollars of tools hanging on the walls. Priorities ,thats all it is.
Yes, line prep and being careful is important but I went throught the flaring issue last year. I was using a KD tool and couldn't figure out why the tubing kept slipping when trying to double flare until I read the instructions. They have an order in the clamp procedure. If I remember correctly you are supposed to start with the low clamp all the way in before clamping the top one. This way puts all the clamp pressure at the top where the flare is. It worked like a champ....they came out beautiful....no cracks.....no need for a magnifying glass.
If all I ever had to flare was brake like I might get by with the hand tool. Did it that way for 20+ years with only the occasional hiccup. But the '65 Mustang convertible (that was supposed to be my wife's birthday present two years ago, with luck it'll run this month) has brake lines (3/16 Cunifer, double-flares and -3 JIC), fuel lines (5/16 and 3/8 Cunifer with GM O-ring flares at the filter, JIC for hard-line-to-hard-line connections, push-connects for the hose connections at the engine, and a bead for the clamped hose at the tank/pump), power steering pressure line from the box to the hose (3/8 steel, JIC) and return/cooler lines (3/8 Bundy, JIC and hose-bead.) That Mastercool thing did them all (bubble-flare dies and three pumps makes a hose bead) and paid for itself as far as I'm concerned...now I'll just put some better tube benders on the wish list, a tube straightener will have to wait until I figure out how to make one...
Thought I should clarify my earlier post. I have plumbed two cars with the new tool, I've been using various other flaring tools since the early 80s. I haven't used a magnifying glass on any of the flares I've done. When I say it was a PITA to get a good flare with the other tools, I mean when I would install the line into whatever fitting I had to attach it to, it wouldn't seal, or I had to tighten it so tight to get it to stop leaking, it would destroy the flare seat into whatever I was working on. I have noticed all the tubing I've tried it with, seems to be thinner wall than the prefabbed ones at the parts stores, and all the mandrels in the tools I have, except the mastercool, fit exceptionally loose in the tube. I always wondered if it was crappy tube, crappy tools, or all thumbs (probably all 3 ). But I never have any issues making a 37* regular flare (non inverted) either single or double, go figure. Of course the tooling for a 37* non inverted double flare is somewhat special, only ever done that in aircraft maintenance school, so the tooling is likely a bit tighter tollerance, as is the tube.
One problem I've had is the small 3/16" line slipping in the dies before the flairing operation is complete. I used a carbide center punch and "dimpled" the inside of the die. Problem solved. I've found there is a lot of latitude in making a leak proof double flair. Obviously a cracked flair will leak but I've used many flairs that were a little off center, not much taper or generally didn't come out right. Oh yeh, I have a Ridgid double flairing set.
Like they say, a man's only as good as his tools. Use a high quality flare tool, put the lines together tight, and the more you do, the more you will build confidence. I never looked at one under a microscope.
I've had great luck with my Imperial flare tool. I spend extra time de-burring the inside and outside of tube, use lube and go sloowly. And like others have said, don't bottom-out the flares. The cheaper tools sometimes don't grip the tubing as well, and that causes problems. Uniformity is key.
I've done the lines on a couple cars, and everything mentioned so far is great advice, especially reaming out the tubing after cutting and getting a 90* cut. One thing in particular I found that really helped weather using a cheap tool or expensive one is to put a drop of oil, or brake fluid on the tubing, or tool, before flaring it. It provides some lubrication between the metal to metal contact and definetely helps the end result.
Yes, and always lube with brake fluid. Or in some cases what ever fluid is going through the lines. Double flares are finesse not force.
A better method would be to rub the mating surfaces of the die halves on a surface plate with some wet and dry to achieve greater "crush" on the tube. Shouldn't need to dimple the surface where the tube sits to provide greater purchase.
Been there and done all but the expensive tools. Went to the hydraulic supplier and found out that they sell lines in 2" increments. They cost more but I didn't have to make any more double flared ends!
I use the Mastercool Universal Hydraulic Flaring Tool Set I've been getting perfect results every time, even on stainless steel lines.
Wet and dry is the rubbing paper used for rubbing down paintwork. A piece of that , a piece of flat plate and some kerosene to help it cut and you're in business.
I got this tool from Classic Performance. It cam locks down on the tube kinda like a vise grip. I've only made a couple of flares but seems to work good if you follow the instructions. http://www.classicperform.com/Store/Tools/CPDFTD.htm later, Timbo
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