Flare Nut Wrench vs Open End Wrench: Which One Should You Buy?

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Flare nut wrench vs open end wrench: the difference

A flare nut wrench, also called a line wrench, has an opening just wide enough to slip over tubing, then closes around five flats of the nut. An open end wrench has a wider jaw that contacts two flats. The DURATECH states its open side lets the wrench fit onto automotive and plumbing tubing lines, with a 15 degree offset at the ends for tighter places. The GEARWRENCH states a 180-degree flexible head for hard-to-reach places. For a soft flare nut on a brake line, the five-flat grip is the design that prevents rounding; for a hard hex bolt in the open, the open end is faster.

Why brake and fuel lines need the flare nut

Line nuts are made of softer materials than ordinary bolts, and the GEARWRENCH listing states its wrenches are ideal for hex nuts made of softer materials. The DURATECH states its wrenches are designed to prevent rounding out edges over time and exceed ANSI standards. The SEDY states its tools clamp the flared nuts of eight common standard sizes on fuel tube hose and transmission lines. When a line nut rounds, the whole line often needs replacing, so the flare nut is the safe choice on anything carrying brake fluid or fuel.

When the open end is fine

No listing here is an open end wrench set, so the open end side runs on the concept. On ordinary hard hex fasteners with full access, an open end turns the fastener without the extra step of slipping the wrench over a line. The flare nut’s advantage is grip on soft nuts; on a standard bolt the open end is quicker and lighter. Own both: the flare nut for lines, the open end for everything else.

Gear: four flare nut sets, ranked by stated contents

1. GEARWRENCH 6-piece flex set

The GEARWRENCH states six metric flex flare nut wrenches: 9×11, 10×12, 13×14, 15×17, 16×18 and 19×21 mm, in alloy steel with a polished chrome finish. The 180-degree flexible head is the stated access story, and the set is the only one here with a 16×18 mm size. It states a standard limited lifetime warranty, the longest stated term here, at 16 ounces.

2. Sunex Tools 9-piece SAE and metric set

The Sunex states nine flare nut wrenches in SAE and metric sizes, fully polished drop forged alloy steel. It states 210 Nm of item torque, the only torque figure here, at 2 pounds. It states a manufacturer warranty with no term, and a canvas pouch.

3. DURATECH 3-piece metric set

The DURATECH states three metric flare nut wrenches, 10×12, 13×14 and 15×17 mm, two sizes per wrench, in chrome vanadium steel with a mirror polish finish. It states the wrenches exceed ANSI standards, the only standards claim here, with a 15 degree offset and a roll-up pouch with sizes printed.

4. SEDY 4-piece metric set

The SEDY states four metric flare nut wrenches, 9×11, 10×12, 13×14 and 15×17 mm, in chrome vanadium steel at 0.43 kg, with a storage pouch. It states a one-piece alloy steel structure for durability. It is the lightest stated set here, and it covers the same popular sizes as the DURATECH with one extra wrench.

What the listings state side by side

Sizes: the Sunex states the widest range at nine wrenches in SAE and metric; the GEARWRENCH states six metric; the SEDY states four metric; the DURATECH states three metric. Materials: the DURATECH and SEDY state chrome vanadium steel; the Sunex states drop forged alloy steel; the GEARWRENCH states alloy steel. Warranties: the GEARWRENCH states a standard limited lifetime warranty; the Sunex states a manufacturer warranty with no term; the DURATECH and SEDY state no warranty term. The DURATECH states it exceeds ANSI standards, the only standards claim here.

Sizes on each end, as stated

The GEARWRENCH states six metric wrenches with ends at 9 by 11, 10 by 12, 13 by 14, 15 by 17 and 16 by 18 mm. The DURATECH states three metric wrenches at 10, 12, 13, 14, 15 and 17 mm with a roll-up pouch that has each size printed. The Sunex states nine wrenches in SAE and metric with a 1/2 to 9/16 in SAE set named. The SEDY states a 4-piece metric set. For brake and fuel line fittings, the stated end sizes are the coverage story.

Finish and storage

The SEDY states polished chrome vanadium steel. The Sunex states a fully polished set. The GEARWRENCH states a chrome finish. The DURATECH states a roll-up pouch with each wrench size printed for organization. For a tool that lives in a toolbox, the stated finish and the printed pouch are the keep-it-found story.

Who these are for

The DURATECH states its set is for mechanics, auto repair technicians and tradesmen who work on lines. The GEARWRENCH states a flex-head design in its set name. For line work, the stated trade use is the relevance story.

Frequently Asked Questions

Can I use an open end wrench on a brake line fitting?

The concept: an open end grabs two flats and rounds soft line nuts, which is why the flare nut exists. The listings here state flare nut wrenches for line fittings.

Which set covers both SAE and metric?

The Sunex states nine wrenches in SAE and metric. The other three state metric only.

Which states the most sizes?

The Sunex states nine wrenches. The GEARWRENCH states six, the SEDY states four and the DURATECH states three.

Which states a warranty?

The GEARWRENCH states a standard limited lifetime warranty. The Sunex states a manufacturer warranty with no term. The DURATECH and SEDY state no warranty term.

Which states it exceeds a standard?

The DURATECH states its wrenches exceed ANSI standards. The others state no standards claim.

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