How to Choose the Best Hex Key Set
With so many available, how do you know which set is right for you? To start, you must determine what style of hex wrench best suits your needs.
The three common types of hex keys are L shaped, T shaped, and fold-up sets. The long arm on L shaped handles produces more leverage than the other hex wrench variants, allowing for higher torque and better reach into tight areas. The T shaped wrenches are used in low torque applications due to their ease of use and torque control. They have relative short wrench lengths and require easy access to sockets. Fold-up sets are convenient as they can fit in your pocket, making them great for doing spot checks on the shop floor. All wrenches are locked into the carrying case, preventing individual sizes from being lost. Like T handles, they have limited torque capabilities and don’t work in space constrained applications.
Now that you know the different styles of hex wrenches, learn what separates the good from the bad.
How durable are they? Most hex wrenches are manufactured from steel, however there are many grades and qualities of steel. Often, hex wrenches are constructed from inexpensive steel grades where hardness, stress relief, and surface treatments are not considered during the design and manufacturing process. This leads to hex wrenches that have lower tensile strength and a shorter lifespan. Replacement will be required more frequently resulting in higher long-term costs and inconvenience to users. If you use hex wrenches infrequently, for low torque applications, or just lose them all the time the cheaper alternative is most likely suitable for your needs.
All hex wrenches are not created equal. If you have ever rounded the corners on your cheap hex wrenches, save yourself the time and effort and look for a more robust set. Maintaining material hardness is critical for high tensile strength which translates into better torque capabilities from the wrenches. Premium manufacturers often specify the Rockwell Hardness rating of their steel tools to differentiate from inexpensive competitors. These are most likely to have a Rockwell rating of C55 and above.
Surface treatments can also impact the lifespan and performance of hex keys. Typically, hex wrenches have a black oxide or zinc plated finish. Both finishes can degrade over time with black oxide wearing leading to rust and zinc flaking off. When comparing tools from different manufacturers it is important to evaluate if the manufacturer offers proprietary or additional surface treatment options. For example, chrome plating is more durable when compared to black oxide or zinc due to reduced friction between the tool end and hardware being installed. It also has better wear resistance, especially when it is textured. This added durability can be a detriment though as it may be easier to over torque or strip out the screw socket. Users need to balance out what features are more important to them.
Are there any design benefits in the wrenches? We already covered the different styles of wrenches, but there are more design factors to consider such as length, end geometry, and bend angle.
Wrench length can be critical depending on the application. Long wrenches are preferred when higher torque is needed or there is limited accessibility, but they also promote over torquing if the user is not careful. Short wrenches are better suited for confined spaces where longer styles will not fit.
End geometry is a major design differentiator. Standard inexpensive hex keys will have a hex end with sharp corners designed to fit the hardware with some play. They must be used perpendicular to the screw, making it more difficult to ensure full engagement. This makes it easy to strip sockets, especially at higher torques, and creates awkward wrist angles that may be uncomfortable for users. An advancement to this is the ball end. They are designed to be inserted into the screw socket at an angle allowing for a more natural grip and smoother torquing. Ball ends are typically only on the long end of wrenches and they save time during installation or disassembly as they do not need perfect alignment to mate with the screw head. It’s important to note that ball ends are only used to start the installation. They do not have full surface contact with the socket, which means they lack the wrench to socket engagement needed to fully torque the screw. Trying to fully torque a screw with the ball end will not work and it may even break the ball end in higher torque applications.
Are there any convenience benefits? We already discussed ball ends which are a major convenience during the insertion into the screw. One of the other common problems on shop floors is losing hex wrenches. They are usually a dark finish and many of the surfaces they are used on are dark as well and cluttered with other tools making them easy to lose. Manufacturers may offer a colored finish on the L shaped wrenches which allows them to be easily identified on the assembly bench, floor, or in the tool box. This reduces wasted time searching for inexpensive assembly tools. Additionally, the color is an indicator of the size of the wrench which makes it easier to pick the correct size quickly.
Another element of convenience is having the size etched or stamped into the wrench. All sets come standard with a labeled tool holder, but what happens when you have multiple keys of close size out of the holder at the same time? You will likely eyeball the keys and use the one of closest fit, which is particularly risky when there are both inch and metric wrenches to choose from. This leaves you fumbling around trying wrenches until one fits or using the size that does the job, but may strip out the socket. On larger wrenches it may be possible to write the size directly on the body, however this is not a solution for smaller sizes. Having the size stamped on the wrench makes identification simple and saves time.
Finally, an important factor with all hand tools is grip. There are all types of different grips on L-wrenches including textured finishes, coatings, rubber or plastic sleeves, cushioned grips, and some are simply shaped to fit your hand. There are pros and cons to all grip types. For example, a paint-type coating may protect the wrenches from rust and damage but the coating may chip off the wrench end and compromise how it fits in the screw head. The primary factor when considering grip is the operating environment. Using them at home to assemble furniture is different than use in a machine shop with oil, coolant, chemicals, and other slick contaminants present. Some applications may require wrenches that can withstand extreme temperatures and not be overly hot or cold to the touch.
Conclusion Clearly, there is no simple answer to the question, “what is the best hex wrench set?” There are plenty of factors to consider and the importance of each factor differs between operating environments and application requirements. We hope this guide gives you enough information to buy the best hex wrench set for you.