DIY flare nut wrench

[supersteve]

It has been proposed to me by another GJ member (name changed to protect the innocent) that one might make one's own flare nut wrenches by cutting a gateway in a common box end wrench, a la this:
http://www.oursuv.com/boards/GMSUV0407/messages/1044.html
It would seem to me that this would spread easily compared to a real flare nut wrench.

Has anyone any experience with doing this?
What brand tools did you use?
Great success or dismal failure?

 

[CJKaz]

Tried it with an old craftsman (80's vintage USA made) combination wrench. It did spread enough to slip & round off the brake line fitting. Got it with vice grips ( wrecked it).

Spend the money for a proper flare wrench, much easier than wrecking the part and the extra work that will surely follow.

 

[thesilverone]

the metal is too thin on the box end

 

[Guns R Tools]

flare wrench are beefier to compensate for openness.

 

[Alchymist]

Did that with a 5/16" box end for RF cable nuts, but then they are only torqued to 10 inlbs. Doubt it would work in a higher torque situation.

 

[rusty65]

I understand using the right tool for the job ,but cheating sometimes works my auto tech teacher took off a flare nut on a rusted out bronco with the open end of a random china wrench.

 

[KinzeMech]

If you absolutely must do something like that in a pinch, boost the strength of the cut out box end by clamping a vise grips on the outside of it (space permitting)

 

[Altec]

I did this to a 7/8 wrench to get a 02 sensor out once. The trick was to put the cut off to one side so it would lock in. I ended up taking it to the junk yards with me to get sensors out. I could stand on the thing.

 

[Provincial]

I used an impact socket to make mine. It has heavy enough walls that it doesn't flex. I made one from a SnapOn socket and another from a HF socket. I don't notice a difference between the two as far as flex goes. Impact sockets are 6 point, of course.

Regular thin-wall hand sockets are too thin to work well. I have seen them spring open a litttle just from cutting the slot.

 

[WVBrady]

...The trick was to put the cut off to one side so it would lock in. I ended up taking it to the junk yards with me to get sensors out. I could stand on the thing.

Good thinking! That makes it almost like a strap wrench.

 

[Stuart in MN]

If you absolutely must do something like that in a pinch, boost the strength of the cut out box end by clamping a vise grips on the outside of it (space permitting)

I've done this before with a conventional flare wrench on a hard to loosen fitting, it works well.

 

[bluebolt]

I've done this before with a conventional flare wrench on a hard to loosen fitting, it works well.

The Vise Grip locking wrenchs are the best thing I have ever found to get stubborn brake fittings loose without rounding off the fitting. I use the model numbers 4LW and 7LW.

 

[supersteve]

The Vise Grip locking wrenchs are the best thing I have ever found to get stubborn brake fittings loose without rounding off the fitting. I use the model numbers 4LW and 7LW.

I have the 7LW, still in the package. I'll have to give them a try sometime, sounds like a good idea.

I just had another thought since we're on the subject of Vise-Grips.
When protecting threaded items that I need to clamp in a vise, I'll often slit a nut with a cutoff tool and then spin the nut onto the threads, instant thread protection while still having the ability to be clamped and held tight in the vise.
I wonder if this could be done with a Harbor Freight 6 point socket, just cut the drive end off and then cut the gate for the line in the side of the socket. Install on the flare nut and then use regular Vise-Grips to clamp and turn the outside of the socket. This would protect the hex on the flare nut from getting chewed up. Maybe use an impact socket so the pliers' teeth don't skid on the chrome.

If that makes any sense.

This is purely a desperation measure, not suggesting this as a common service application. I suppose this probably wouldn't work as well as the Vise-Grips on the box end wrench suggestion, where the wrench handle provides the turning force.

 

[KinzeMech]

I did this to a 7/8 wrench to get a 02 sensor out once. The trick was to put the cut off to one side so it would lock in. I ended up taking it to the junk yards with me to get sensors out. I could stand on the thing.

Why not just unplug the sensor, and use the box end without breaking it open?

 

[supersteve]

I did this to a 7/8 wrench to get a 02 sensor out once. The trick was to put the cut off to one side so it would lock in. I ended up taking it to the junk yards with me to get sensors out. I could stand on the thing.

You don't remember what brand of wrench, do you? Something beefy?

Why not just unplug the sensor, and use the box end without breaking it open?

I've seen a couple where the connector doesn't want to thread through the box end without either breaking the connector or cutting the wires.

 

[Outlawmws]

I have a couple floating around here somewhere I think, that other people made that way. I've also seen them (Flea markets/yard sales) made that way and are now broken completely as they were too weak.

I've had Flare wrenches since I was a teenager so never needed to cut one.

2X on the Nut gripping Vise grips though, they work if you have clearance.

 

[Altec]

You don't remember what brand of wrench, do you? Something beefy?



I've seen a couple where the connector doesn't want to thread through the box end without either breaking the connector or cutting the wires.

Yes I do. It was a old Sears branded combo that was made in Japan. Far from beefy. The fact that it was able to grab like it did astounded me. It sits in my box for a rainy day.