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You asked for it, the Flarenut Wrench Brands that DON'T slip are these

SRSemenza

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Apr 26, 2017
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616
Nice test.


It would be great to see this type of test done with thin / slim open end wrenches.


Seth
 
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CallumRD1

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Colorado
Appreciate the thread and resources required to put it all together. I personally would have liked to see if there was any change with the open end measurements after the test. In theory, unless it’s just the butter the wrench hardness should supersede the fitting. With that said.. I’ve junked or put in the warranty box my fair share of line wrenches due to visible spread.

Just a thought..
I'm not sure where you're going with this. The stiffness of steel (Young's modulus, the propensity to resist deflection) is effectively independent of hardness. It's a property of the steel composition and geometry. The fit of the tool on the fastener determines the geometry of the interaction and a tighter fit will mean that a greater deflection of the open end will be required prior to the wrench slipping. A well heat treated piece of steel like these wrenches will deform elastically in this case and not take a set. When the wrench spreads and rounds a bolt the wrench doesn't end up plastically deformed with the jaws no longer parallel.
 

Hiball

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Missery
I'm not sure where you're going with this. The stiffness of steel (Young's modulus, the propensity to resist deflection) is effectively independent of hardness. It's a property of the steel composition and geometry. The fit of the tool on the fastener determines the geometry of the interaction and a tighter fit will mean that a greater deflection of the open end will be required prior to the wrench slipping. A well heat treated piece of steel like these wrenches will deform elastically in this case and not take a set. When the wrench spreads and rounds a bolt the wrench doesn't end up plastically deformed with the jaws no longer parallel.
I suppose I’ve owned some steel that wasn’t “well treated”, Because they have definitely taken a “set” over the years.

I didn’t realize I was trying to “go” anywhere crazy, it was just a simple question and observation.
 

qqzj

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Nov 28, 2017
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3,747
Could you imagine if project farm did this comparison?
Hard to say. This one just 'happened' to confirm the popular opinion that Snap On is the best. There are plenty of video from TTC that does not. Like a junky brand on Amazon 1/2 impact wrench is same as a Ridgid. I have a full set of the type of China-made Cman flarenut wrench as tested here and I am very happy. No need to consider SK at least. I am in California, there is definitely no need for me to buy more expensive stuff.
 

unslow1

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I suppose I’ve owned some steel that wasn’t “well treated”, Because they have definitely taken a “set” over the years.

I didn’t realize I was trying to “go” anywhere crazy, it was just a simple question and observation.
Is the wrench spread permanent seems like a logical question.
 

Mr_B

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I'm not sure where you're going with this. The stiffness of steel (Young's modulus, the propensity to resist deflection) is effectively independent of hardness. It's a property of the steel composition and geometry. The fit of the tool on the fastener determines the geometry of the interaction and a tighter fit will mean that a greater deflection of the open end will be required prior to the wrench slipping. A well heat treated piece of steel like these wrenches will deform elastically in this case and not take a set. When the wrench spreads and rounds a bolt the wrench doesn't end up plastically deformed with the jaws no longer parallel.
my experience in 30 years of using them says otherwise .
 

redwrench60

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East Tennessee
People who don’t work on a wide variety of vehicles or machinery to make dollar bills won’t understand. Nothing like a hopelessly rounded flare nut in an impossibility tight spot to ruin a quick and profitable job. I cycled through a couple brands of line wrenches before I figured out Snap-on had the best. Occasionally you’ll still find one too tight and corroded to rescue but the Snappys give you the best shot.
 

BlitzcrankJapan

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Dec 9, 2019
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Gold Coast, Australia
It looks like the wrench size is what's mattering here. Not just the wrench spreading.

I wonder if you could just pick a tight tolerance cheaper wrench and it would work almost as good as the snap on?
I also wonder if all of the snap on wrenches measure this tight, or did they get lucky with the two wrenches measuring tight.

P.s. this is precisely what brands like Koken's ZEAL range and KTC Nepros advertise. Holding tolerances much closer than standard.
Really it just means that more QC checks need to be in place, and most costly the tooling must be replaced more regularly.
 

velillen01

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Wyoming
It looks like the wrench size is what's mattering here. Not just the wrench spreading.

Thats the only area I wish we could have seen tested.. Wish instead of doing the 1/2" - 9/16" range they could have added the more common brake line fitting sizes (8/10mm 3/8-5/16). Would have been an interesting comparison to see if the smaller sizes experience the same "issues" as the bigger sizes. For DIY those are probably more commonly found/used sizes too.

Still cant complain on their test though! Was interesting to see how everything performed.
 

Old Donn

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Michigan
Have a set of Cman RP and SK line wrenches. As a DIY'er, I'd take both, use whichever fit the tightest.. Recently picked up Knipex flare nut pliers. I'll be doing some brake work on the avatar this spring, we'll see if the Knips were money well spent.
 

RickyPetite

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Oct 12, 2019
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Buck's County, PA
Your hard work is greatly appreciated. Nothing like actual data to confirm (or disprove) brand bias. I have always noted how bulky my SK line wrenches were. Never rounded a fastener but also have trouble getting into tight spots. Your video answered why they are designed this way...harder steel is more brittle so more of it is needed to avoid shattering.
 

Mr_B

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on brake lines that trying to save a section and got space I always using 4lw 7lw or 7r .
Only real time i'm using flare nut wrenches is very tight work and that normally valve blocks or abs pumps for brakes or diesel fuel lines and hydraulic farm/construction equipment . Snapon always seemed nicer fit and less feeling of spread over others i've used .
Never tried stahlwille or gedore but might pick up a common size for a trial .
Craftsman China was the real surprise results ...
 

unslow1

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I live in Illinois so the go to brake line tools are a pair of visegrips, torch and snips. It's pretty rare to get a fitting loose unless it's pretty new.
 
OP
T

Torque Test Channel

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Thats the only area I wish we could have seen tested.. Wish instead of doing the 1/2" - 9/16" range they could have added the more common brake line fitting sizes (8/10mm 3/8-5/16). Would have been an interesting comparison to see if the smaller sizes experience the same "issues" as the bigger sizes. For DIY those are probably more commonly found/used sizes too.

Still cant complain on their test though! Was interesting to see how everything performed.
We have comments about this too. We used the smallest size who's threads weren't the weak point. On a 10mm or 3/8" hex bolt, the thread size needed is tiny. You end up killing threads on a small soft hex nut way before learning anything about the wrench. 9 out of 10 wrenches max out the threads, nothing to measure there. That lesson cost us a few hundred bucks lol.

Its also not only about hex tolerance. It's a good piece of the pie however.
 

unslow1

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We have comments about this too. We used the smallest size who's threads weren't the weak point. On a 10mm or 3/8" hex bolt, the thread size needed is tiny. You end up killing threads on a small soft hex nut way before learning anything about the wrench. 9 out of 10 wrenches max out the threads, nothing to measure there. That lesson cost us a few hundred bucks lol.

Its also not only about hex tolerance. It's a good piece of the pie however.
Thanks for the explanation. I was also wondering why you didn't use bleeder sizes.
 

rlitman

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Long Island
Thanks for the explanation. I was also wondering why you didn't use bleeder sizes.
You can usually put a box wrench on a bleeder, and being a closed ring, even a cheap box wrench will likely outperform a Snap On flare nut wrench. Plus box wrenches will be thinner wall.
 

msharley

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A point that many of the posters are missing.

Is the DESIGN of the Wrench.

The engagement surfaces of the SNAP ON Wrenches is closest to being flush. Much less "lead in" taper than with the other makers.

This allows the SNAP ON Wrench to engage more of the fastener.

Many times, these fasteners are pitifully shallow, and a wrench from "other makers" has so much "lead in"...that it will barely engage the top of the fastener....

If one were to hold the wrenches side by side....this is readily visible...

I have a set of Snap On & a set of MAC line wrenches (some others in the "mixed wrench drawer") for the simple reason that the "index" is different. In a tight spot, loosen the fastener the first little bit with one (or the other) then switch to loosen the next little bit with the other brand.

Many areas around hydraulics do not permit a SIXTY DEGREE "swing" of the wrench.

The fasteners that can be readily loosened with these two brands of line wrenches is amazing. Compared to the amount of fasteners that can be RUINED using other brands of line wrenches.

My third choice in line wrenches would be the KD brand...used to be handled by the local parts store....(not sure if they still make those?)
 
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unslow1

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You can usually put a box wrench on a bleeder, and being a closed ring, even a cheap box wrench will likely outperform a Snap On flare nut wrench. Plus box wrenches will be thinner wall.
I have a set of 6pt box end wrenches I bought just for bleeders. Sometimes I get lucky and they even work on rusty ones.
 

n8n

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Mar 11, 2014
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Curtis Bay, MD
I'm not sure where you're going with this. The stiffness of steel (Young's modulus, the propensity to resist deflection) is effectively independent of hardness. It's a property of the steel composition and geometry. The fit of the tool on the fastener determines the geometry of the interaction and a tighter fit will mean that a greater deflection of the open end will be required prior to the wrench slipping. A well heat treated piece of steel like these wrenches will deform elastically in this case and not take a set. When the wrench spreads and rounds a bolt the wrench doesn't end up plastically deformed with the jaws no longer parallel.

I have seen exactly that happen though. It shouldn't, but it does. (RP Craftsman, probably purchased new circa Y2K, even before China production)
 

n8n

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We have comments about this too. We used the smallest size who's threads weren't the weak point. On a 10mm or 3/8" hex bolt, the thread size needed is tiny. You end up killing threads on a small soft hex nut way before learning anything about the wrench. 9 out of 10 wrenches max out the threads, nothing to measure there. That lesson cost us a few hundred bucks lol.

Its also not only about hex tolerance. It's a good piece of the pie however.
I have irreparably spread a 10mm flare wrench before; its not tightening that's the problem, it's trying to loosen a steel nut that's been in an aluminum block for 15+ years...
 

n8n

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A point that many of the posters are missing.

Is the DESIGN of the Wrench.

The engagement surfaces of the SNAP ON Wrenches is closest to being flush. Much less "lead in" taper than with the other makers.

This allows the SNAP ON Wrench to engage more of the fastener.

Many times, these fasteners are pitifully shallow, and a wrench from "other makers" has so much "lead in"...that it will barely engage the top of the fastener....

If one were to hold the wrenches side by side....this is readily visible...

I have a set of Snap On & a set of MAC line wrenches (some others in the "mixed wrench drawer") for the simple reason that the "index" is different. In a tight spot, loosen the fastener the first little bit with one (or the other) then switch to loosen the next little bit with the other brand.

Many areas around hydraulics do not permit a SIXTY DEGREE "swing" of the wrench.

The fasteners that can be readily loosened with these two brands of line wrenches is amazing. Compared to the amount of fasteners that can be RUINED using other brands of line wrenches.

My third choice in line wrenches would be the KD brand...used to be handled by the local parts store....(not sure if they still make those?)
Once busted loose, or when assembling, 12 point flare wrenches are also an option. I made some out of Harbor Freight combo wrenches for the specific task of assembling the power steering on a 64 Studebaker (think GM style ram PS) I would definitely use my Snap-On for breaking loose though!
 

n8n

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I have a set of 6pt box end wrenches I bought just for bleeders. Sometimes I get lucky and they even work on rusty ones.
I pick up 6 point box and combo wrenches whenever I see them cheap. Mostly RP Craftsman but as you say still better than 12 point or flare.
 

velillen01

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May 20, 2015
Messages
481
Location
Wyoming
We have comments about this too. We used the smallest size who's threads weren't the weak point. On a 10mm or 3/8" hex bolt, the thread size needed is tiny. You end up killing threads on a small soft hex nut way before learning anything about the wrench. 9 out of 10 wrenches max out the threads, nothing to measure there. That lesson cost us a few hundred bucks lol.

Its also not only about hex tolerance. It's a good piece of the pie however.

Makes sense! Thanks for the explanation!
 

Mgdoug3

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Mar 2, 2018
Messages
1,391
Location
KY
Once busted loose, or when assembling, 12 point flare wrenches are also an option. I made some out of Harbor Freight combo wrenches for the specific task of assembling the power steering on a 64 Studebaker (think GM style ram PS) I would definitely use my Snap-On for breaking loose though!
I have 1/2" to 3/4" Snap-on wrenches in 12 point that are great to use in tight spots but for really tight bolts they will slip. The 3/4" one I use the most for injector lines. Usually they're not too tight and 12 points makes it much easier in tight spots.

My great uncle gave me those wrenches and they're probably from the 70s but they still work great.
 

Steve_P

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Sep 15, 2010
Messages
5,185
I'm not sure where you're going with this. The stiffness of steel (Young's modulus, the propensity to resist deflection) is effectively independent of hardness. It's a property of the steel composition and geometry. The fit of the tool on the fastener determines the geometry of the interaction and a tighter fit will mean that a greater deflection of the open end will be required prior to the wrench slipping. A well heat treated piece of steel like these wrenches will deform elastically in this case and not take a set. When the wrench spreads and rounds a bolt the wrench doesn't end up plastically deformed with the jaws no longer parallel.

Yes, the stiffness is independent of hardness - and I know this doesn't make sense most men LOL. With like materials, including alloy steel vs mild steel, the elastic deflection is based on geometry of the stressed area- and not the alloy and heat treatment. Heat treated 4340 has essentially the same "E" (Young's) as A36 -mild steel; same geometry under the same load, they will deflect the same elastically; but A36 will plastically deform waaaaay prior to 4340. I know the elastic deflection point being equal doesn't make sense, but it's true.

My point on "everything spreads" is that any steel, even mildly heat treated 1040, is going to round a tube fitting before the wrench "spreads". On tube fittings, it's not wrench spreading, it's the fit, engagement, etc that rounds off the fitting.

And if you are doing the last portion of the test with heat treated bits, then yes, hardness, etc matters. But this doesn't relate to tube fittings.

And some rusty sh!t just isn't going to loosen, no matter what brand tool you have...
 

anndel

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Oct 28, 2015
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Hawaii, USA
I love my Snap-on and they haven't rounded off bleeders yet. Rounded off several using Tektons. Had to buy a Proto 8mm since most Toyota's I've been working on had 8mm bleeders.
 

DGersic

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Mar 12, 2017
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DeKalb, IL
I just watched this last night. Well done. You did a nice job of empirical testing. The only problem I have is that I’m not working on clean threads with wide open access. I’m working on rusty fittings, at weird angles, little to no visibility, and with little clearance to actually turn the wrench. If it rounds, it just gets worse.

I have the newer Craftsman, and a set of SnapOns. The SO are better but the nuts are soft and round off anyway.
 

SRSemenza

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Apr 26, 2017
Messages
616
Have a set of Cman RP and SK line wrenches. As a DIY'er, I'd take both, use whichever fit the tightest.. Recently picked up Knipex flare nut pliers. I'll be doing some brake work on the avatar this spring, we'll see if the Knips were money well spent.

Got a link or product # for the Knipex?

Seth
 

Fedwrench

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Valley of the sun
@Torque Test Channel
It would have been interesting to see how the FD+ open end performed in this test.
There ya go, the Torque Test Channel can test the various anti slip open ends found on combination wrenches such as wright grip, Proto ASD, Carlyle, Harbor Freight, Gearwrench, MAC precision Torque, Snap on, and even the new Die Hard. :beer:
 
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