Avoid Rounding Bolt Heads With The Best Flare Nut Wrenches

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Click here to see examples of flare nut wrenches.
Click here to see examples of flare nut wrenches.
When working on your car, there are certain times when you will encounter screws that you simply can’t get a box end wrench on based on the geometry of the part (one great example is when tightening brake line fittings during a brake bleeding procedure where the brake line itself prevents you from getting your box wrench on the nut). Some of these screws can still have decently high torque specs, and can thus require some considerable force to loosen. Using a regular open wrench can work, but using an open wrench to loosen a tight bolt is a good way to round the corners on the bolt head or nut that you are trying to loosen. In these cases you need a wrench that is both open but provides more contact area on the bolt head than a normal open wrench.

Fortunately there is a very common type of wrench that affords you this capability: the flare nut wrench. A flare nut wrench behaves exactly like an open wrench, except that it wraps around more of the head of the nut or bolt. This allows you to clear obstacles that otherwise prevent other types of wrenches from engaging a bolt.

When picking a flare nut wrench, there are tons of small variations and configurations. Some of them are straight, some of them have angled heads, some have flexible heads, some come in kits, and some are sold individually. In general, the best flare nut wrench sets contain both metric and standard sizes we recommend making sure you have both (either in one kit or as two separate kits) to ensure that your bases are covered.

The Best Flare Nut Wrenches

tekton flare nut wrenches
Fortunately, flare nut wrenches are relatively simple tools. Unless you are looking for a flex head (which adds bulk to the head and limits your access in tight spots so we don’t consider a flex head worth the tradeoff) there are no moving parts and really nothing to fail other than the steel itself. As such, there isn’t a ton of value in springing for the more expensive Craftsman or Gearwrench sets. Instead, the best value flare nut wrench sets to be had are made by one of our emerging favorites for cheap tools: Tekton.

Tekton makes flare nut wrench sets in both metric and SAE sizes, and they also make short (also known as stubby) flare nut wrenches as well as long flare nut wrenches. The benefit to the stubby wrenches is that they are short enough to give you better access in some tight spaces. However, relative to their longer counterparts, you have to work harder to apply the same amount of torque. We typically recommend starting out with the longs as the stubby wrenches just aren’t useful that often in our experience.

Tekton’s flare wrench sets grip 5 sides of the nut or bolt you are engaging which nicely spreads the pressure and protects the head of the bolt or nut from damage. The ends are offset a modest 15 degrees, which is enough to give you some extra clearance under certain circumstances. The build quality is excellent, especially considering the price point, and this fact is punctuated by a svelte mirrored chrome finish which makes Tekton’s wrenches rust resistant as well as rather pleasing to look at.

Overall, we think you will be extremely happen with Tekton’s flare nut wrenches as they will make life in the garage and under the hood that much easier. As far as where to buy, Amazon usually has excellent prices and is a good way to find them on the cheap.


Every mechanic should have a set of flare nut wrenches in their tool chest! They will speed your work on your brake lines, A/ lines, fuel lines, and even your cooling lines on certain makes and models of cars. While we think the Tektons are the best flare nut wrenches for the money, there are a ton of other options out there so take a second to have a look by clicking here if you feel so inclined. Happy wrenching!