What are Flare Nut Wrenches for?

[Jacobson]

When do you need a flare nut wrench?
What situation or fastener where a regular wrench not work?

http://www.sears.com/craftsman-5-pc-flare-nut-wrench-set-metric/p-00942013000P

 

[Zeroek]

I used those on brake line fittings.

 

[SteveCh]

Flare nut wrenches are good for situations, such as brake lines, where they give more points of contact on the nut than an open-end wrench and thus more likely prevent damage to the nut. Especially brass nuts. You can't use a box-end wrench but the flare nut is a good compromise. I have found them handy in other situations where a nut is difficult to get a good grip on with an open end and the flare nut has that little bit more contact and breaks the nut loose.

 

[Jacobson]

Ok, I did a little more reading.
It sounds like they're box end wrenches but with an opening. For fuel lines?

When should you use an open end wrench instead of a flare/box end?
The box/flare wrench offers more contact surface for softer metals?

 

[Jacobson]

Thanks Steve. It sounds like flare is better for more contact area but when you can't use a closed box end. So, when should you ever bother using open end wrenches if you have both box end (best) and flare nut (2nd best) ?

 

[SteveCh]

The flare-nut wrenches I have [USA Craftsman] are thicker than regular box-end wrenches, I assume for strength. So sometimes the box-end is gonna be easier to get on a nut in tight spaces. The flare-nut wrench, made too thin, can spread, or so I assume. You can put more power behind a box-end than an open-end, all things being equal. Again, the flare-nut compromises.

And, again, I've had situations where an open-end wrench would fit on a jammed or rusted-on nut and the space was too tight for an open-end, the flare-nut wrench would fit in there and have less of a danger of rounding over the nut than the open-end.

 

[dsimatt]

Those wrenches are for mainly line fittings line brake or fuel lines and mainly higher torque situations that a normal wrench would slip and strip the bolt head, also can fit in tighter spots to.

That said i had a set of those crafstman wrenchs and they did nothing but spread and strip when i tried to use them so try to find used higher quality ones that won't spread on you. I've found that if it not a tight fit i take my bigger straight vise grips get them on real tight and hit it with a dead blow because if those strip it then its not coming loose.

 

[AndyA]

Thanks Steve. It sounds like flare is better for more contact area but when you can't use a closed box end. So, when should you ever bother using open end wrenches if you have both box end (best) and flare nut (2nd best) ?

Use the open end when the flare nut won't fit! Sometimes the line it too large a diamater to get the flare nut wrench over it.

I'll also use the open end on something that's already loose and in no danger of rounding. It seems to be faster.

 

[Wakefield]

Flare nut wrench should only be used when some other kind can't be? "line wrench"
Weaker than regular open end (because its more compact without the hip) but easier on soft things like brass and plastic(less apt to round)?
German designs with a ledge/ roofed opening that are said to be extra strong?

(edit) it is my belief that conventional flare nut wrenches are weaker than such open end wrenches as Wright Grip and Flank Drive Plus. If a flare nut wrench were made on the fat hip open end pattern it would be stronger but might not fit everywhere that the traditional ones fit. I believe Nepros and some of the Germans have a few flare nut wrenches like that and also some oxygen sensor tools look like a heavy deep flare wrench with a flex joint. Bonney seemed to have made an extra thick flare wrench.

 

[smiffy]

also on hydraulic spool block on machinery if you want to change the middle pipe you often have to either take all the pipes of or use a flare nut wrench as the fittings are to close together

 

[mtwaterguy]

Use the open end when the flare nut won't fit! Sometimes the line it too large a diamater to get the flare nut wrench over it.

Where would this ever happen?

 

[kiatech]

Where would this ever happen?

Go look at the hose on your compressor.

 

[pburressiii]

Hydrolics


Sent from my iPhone using Tapatalk

 

[slyonedoofy]

I checked out the Sears web page you looked at. All the new polished flare nut wrenches are made in China.

So be prepared for that if you buy them.

I used to be a Home Improvement ASM at Sears so trust me, they will most likely not be the professional branding as shown in the picture.

If anyone has questions about Sears I am very willing to answer.

 

[treblarefils]

I just changed my fuel filter and I had to use a 14mm flare wrench on the inlet fitting. Pretty much on a car that's had the filter on for many years the nut is so tight you have to use a flare wrench or you will ruin the fitting. Some times you get lucky but in my case an open wrench probably would have destroyed the fitting. I dont use them often so I just have the husky flare wrench set from home depot its pretty nice for 20 bucks.

 

[sonvolt]

Brake and fuel lines, hydraulics and situations where a line goes through the ID of a nut/fastener.

 

[mototexas]

I happen to use them in tight places when working in {tight} engine bays, works like a dream

 

[arsco]

the flare nut will deform under load from a wrench and cause it to bind on the threads. the more you can spread the load the less likely it will deform.

 

[zcbauer89]

On farm machinery they are great for hydraulic lines too. Most hydraulic lines are a ***** to get to on newer tractors.

 

[hsnedigar]

On farm machinery they are great for hydraulic lines too. Most hydraulic lines are a ***** to get to on newer tractors.

I hear that, utility tractors when the loader valves runs up the fender such a pain in the neck to do anything with I use to work with a guy he took a cheap 15/16 wrench and ground down the side walls of the opening worked great for 7 years then it broke. but 7 years on a $10 tool that you take most of the structural integrity out of pretty much pays for its self ten fold

 

[rlitman]

The flare-nut wrenches I have [USA Craftsman] are thicker than regular box-end wrenches, I assume for strength. So sometimes the box-end is gonna be easier to get on a nut in tight spaces. The flare-nut wrench, made too thin, can spread, or so I assume. You can put more power behind a box-end than an open-end, all things being equal. Again, the flare-nut compromises.

And, again, I've had situations where an open-end wrench would fit on a jammed or rusted-on nut and the space was too tight for an open-end, the flare-nut wrench would fit in there and have less of a danger of rounding over the nut than the open-end.

Shallow flare-nut wrenches are thicker than box wrenches to prevent spreading. Deep style flare-nut wrenches are no thicker than a box wrench. I have shallow doubled ended flare-nut wrenches, and deep flare-nut crows foot sockets.

 

[wild cowboy]

Brake and fuel lines, power steering and transmission lines, are the most common automotive situations - this is why the flare nut wrench is often referred to as a LINE WRENCH.

 

[Jacobson]

The reason you need a flare nut wrench, and not an open ended one
is b/c there is more surface contact area? This will prevent stripping the fittng.
Then why not use flare nut for ALL situations? What is the downside?

When do you need more contact area? Just for softer fittings like brass?

 

[DanInVA]

Re: Re: What are Flare Nut Wrenches for?

The reason you need a flare nut wrench, and not an open ended one
is b/c there is more surface contact area? This will prevent stripping the fittng.
Then why not use flare nut for ALL situations? What is the downside?

When do you need more contact area? Just for softer fittings like brass?

Flare nut wrenches do offer better grip than open end wrenches, but are slow to use. They can also be harder to use in confined spaces. In addition to that, there are times when a flare nut won't fit. For example, if you were doing a front end alignment on a car with rack and pinion steering, you couldn't use a flare nut to adjust the inner tie rod. A flare nut wrench doesn't have enough of an opening to fit over the tie rod, but an open end will slide right over and you can adjust the tie rod. Hope this helps

 

[bonneyman]

Ratcheting flare wrenches are even better! For repetitive jobs they can really save your wrist.

Although, the Bonney design is so thick getting into tight spots can be a deal killer.

 

[steveo3002]

ive got the craftsmans and they arent very good at all

id suggest you look for another brand for that style of tool

 

[1950mercury]

Flare nuts silly

 

[Cope]

Thanks Steve. It sounds like flare is better for more contact area but when you can't use a closed box end. So, when should you ever bother using open end wrenches if you have both box end (best) and flare nut (2nd best) ?

I would not use flare nut wrenches for higher torque fasteners. I have a set of Snap On flare nut wrenches fro 1968 that are marked Not Guaranteed.

 

[Nick Danger]

Refrigeration, hydraulics, brake fluid, fuel . . . any application where you have to be sure you won't deform the nut because deforming the nut will mean that you won't have a good seal. The nut for a compression fitting often has thinner walls than an ordinary nut.

 

[rlitman]

I would not use flare nut wrenches for higher torque fasteners. I have a set of Snap On flare nut wrenches fro 1968 that are marked Not Guaranteed.

BS. A flare nut wrench will always handle more torque than an open crescent wrench.

The Not Guaranteed mark on a Snap On tool was because they were either originally sold to the government, or an industrial contractor at a discount.

 

[Cope]

BS. A flare nut wrench will always handle more torque than an open crescent wrench.

The Not Guaranteed mark on a Snap On tool was because they were either originally sold to the government, or an industrial contractor at a discount.

I meant where an open end or box end wrench would be used, but maybe they would be fine.

The comment about a government or industrial contractor makes sense. The guy I bought them from was getting out of the aviation industry and going to NASA in Alabama here he wouldn't need any tolls. I bought them for $1.25 each in 1970 and the date stamp is 1968.

 

[bcradio]

BS. A flare nut wrench will always handle more torque than an open crescent wrench.

The Not Guaranteed mark on a Snap On tool was because they were either originally sold to the government, or an industrial contractor at a discount.

I call BS on your BS if you are talking about a standard open end wrench. If you are talking about an adjustable wrench, then I might agree with you. I would argue that an open end wrench (not adjustable) will handle more torque than a flare nut wrench. The heads are typically much thicker on the open end than the flare nut.

Flare nut wrench if you don't want to damage the fastener.
Open end if you need access plus more torque than the flare nut, but are not working with overly delicate fasteners.

 

[f575gtc]

Imagine a brass EGR fitting on the back of an engine block that has heated and cooled many times, that nut is going to be stuck on there and a normal open ended wrench only gives you three points of contact. On a soft metal you will strip the nut.

I bought my cheap set at HF, made in china, paid $7 with a coupon for a set with sizes 10mm to 19mm skips 16mm i think. I used it to remove a EGR nut on the back of a Subaru motor, I pulled and pulled, used a pipe for more leverage and the wrench did not break.

I had previously stripped the nut a bit using an open end wrench and the flare didn't help at that point so the vise grips were eventually needed.

 

[dnschmidt]

One thing a flare nut wrench is great for is removing and installing Oxygen Sensors. The 22mm size is what these typically take and the flare nut wrench goes over the wires and doesn't crush the thin metal shells these are housed in.

 

[bonneyman]

One thing a flare nut wrench is great for is removing and installing Oxygen Sensors. The 22mm size is what these typically take and the flare nut wrench goes over the wires and doesn't crush the thin metal shells these are housed in.

This!
And if you can get enhanced broaching, the chances of crushing and rounding the nuts drops even further. I've found the full polish Bonney's to be really good on HVAC fasteners But they didn't make them in metric.

 

[devoncoolman]

Um flare nuts.

 

[davethorik]

This!
And if you can get enhanced broaching, the chances of crushing and rounding the nuts drops even further. I've found the full polish Bonney's to be really good on HVAC fasteners But they didn't make them in metric.

I have a Bonney combo wrench with a flare nut end and a normal box end, both 7/8. It doesn't have any offset, which is nice in certain situations.

 

[Exceller8]

They're for 3/4" x 6" lag bolts.

 

[azhatchback]

Ratcheting flare wrenches are even better! For repetitive jobs they can really save your wrist.

Although, the Bonney design is so thick getting into tight spots can be a deal killer.

That is cool! How do you like them. That is my biggest complaint with flare wrenches. How long it takes in a tight spot.

I use mine for automotive mostly but was glad i had them when I had to repair my hot water heater. At some point they will come in handy for home use.

 

[azhatchback]

This!
And if you can get enhanced broaching, the chances of crushing and rounding the nuts drops even further. I've found the full polish Bonney's to be really good on HVAC fasteners But they didn't make them in metric.

These look very interesting as well. These would be super in really tight spots. Thanks for the Bonney wrench posts. I will look into these for sure!