DeWalt 1/4 in Drive Standard Length Metric Socket - 6 Point

I reached for this DeWalt 4 mm impact socket while assembling a micro-quad drone that uses M2 hardware. Small hex nuts are easy to round and maddening to access, especially when they sit in carbon fiber cutouts with just a few millimeters of clearance. After a week of on-and-off use across that build and a couple of electronics enclosures, this little socket proved more capable than its size suggests.

Build and materials

This is a standard-length, 6-point, 1/4 in drive socket with a black oxide finish. It’s made from heat-treated CR-440 steel, and in hand it feels dense and neatly machined—no burrs, clean broaching, and a consistent finish. The chamfer at the mouth is modest, which helps start on a nut without leaving you hunting for engagement, but it’s not so aggressive that it compromises grip on tiny flats.

Impact-rated sockets in this size can be overbuilt and bulky at the nose, but the dimensions here strike a useful balance. The socket’s overall length is 29/32 in, the nut-end outside diameter is 9/32 in, and the drive end OD is 1/2 in. In practice, that slim 9/32 in nose helped me get into tight cutouts on drone frames and small brackets without wedging the socket against surrounding material. The black oxide is even and matte, with just enough texture to handle well when your fingers are dusty or oily.

Geometry and grip

DeWalt’s DirectTorque geometry is a flank-drive style that shifts the load off the corners and onto the flats of the fastener. On a 4 mm hex nut, that matters. Small nuts don’t offer much meat, and it’s easy to shave corners with a traditional, corner-biased broach. I intentionally tested this on a few scarred M2 nyloc nuts pulled from a previous build. The socket seated confidently and turned without chatter or cam-out. You can feel it draw down onto the flats as you apply torque, which reduces the anxiety of rounding a fastener you can’t easily replace.

The 6-point configuration is the right choice at this size. Twelve-point sockets are great for speed on larger hardware, but on miniature hex, you want as much contact area as you can get.

Access in tight spaces

Access is the whole game with a 4 mm socket. The standard length means you don’t gain reach like you would with a deep socket, but you do gain control. In a drone stack-up where stand-offs crowd the nut, the short body kept the ratchet head close to the work, reducing wobble. That said, you should know the internal clearances: bolt clearance depth is 11/32 in and nut depth is 3/16 in. If you’re dealing with long protruding studs or tall nyloc nuts, you may bottom out. For those cases, a deep socket or a nut driver is the better tool.

Still, for typical M2 hardware and low-profile nuts, I had no trouble clearing threads and getting full engagement. The slim nut-end OD makes a bigger difference than you might expect—being able to slip between a standoff and a frame plate is often the difference between finishing a job and tearing the assembly back apart.

Drive options and retention

I used this socket primarily on a fine-tooth 1/4 in hand ratchet and a compact 12V cordless ratchet. The detent in the socket’s square drive seats on both tools securely, and the through-hole is properly sized for an O-ring/retaining pin if you’re running it on a micro impact wrench or a square-drive adapter that uses pin retention. Positive retention matters more than you think with tiny sockets; it keeps the socket from staying behind in a tight recess when you back out the ratchet.

As for impact use, I did test it briefly on a low-torque 1/4 in impact ratchet to break free a stubborn nyloc. It handled it without complaint, which is reassuring; the impact rating is as much about durability in day-to-day abuse as it is about repeated hammering. That said, there’s no scenario where I’d recommend hammering a 4 mm nut with a full-on impact wrench—save the rating as a proxy for toughness, not an invitation to over-torque tiny fasteners.

Markings and day-to-day usability

The size is laser-etched in high-contrast characters. On a black oxide socket, clear markings are essential, and these are easy to read at a glance. After a handful of uses, the etching is still crisp. Over the long haul, etched markings can lose some contrast as oil and grime fill the lettering; a quick wipe with solvent brings them back. I’d still love to see a backup stamped mark for absolute permanence, but the etch here is better executed than many I own.

The finish forgives drops and bench knocks without showing bright scars like chrome. I also appreciate that the exterior profile is simple and round—no ornamental flats to snag in tight cavities. It’ll roll on a sloped bench like most sockets, so keep a tray handy if you’re working over concrete.

Durability and corrosion resistance

Heat-treated CR-440 steel feels like the right call here. There were no signs of deformation in the broach after trying it on a few hardware-store nuts I intentionally over-torqued by hand. The black oxide coating resists glare and provides basic corrosion resistance, but like any black oxide, it’s not a barrier coating. If you leave it wet, it will develop surface oxidation. A light film of oil or a silica gel packet in your socket drawer goes a long way. I tossed it in a damp tool bag for a day as a test; it came out fine, though I wiped a faint watermark from the surface without trouble.

Where it shines—and where it doesn’t

This socket makes the most sense for:

• RC and FPV builds that use M2 hex nuts
• Small robotics and mechatronics fixtures
• Electronics enclosures or brackets with miniature hardware
• Precision work where a hand ratchet and good feel matter

It’s less ideal for:

• Long studs or stack-ups that exceed the 11/32 in bolt clearance
• Situations that demand a deep socket or nut driver reach
• Users who prefer hard-stamped size markings
• General automotive work (a 4 mm socket simply isn’t common there)

If you often find yourself improvising with a nut driver or pliers on tiny hardware, moving to a properly sized impact-rated socket like this dramatically reduces the chance of damage.

Warranty and support

The full lifetime warranty is the kind of quiet reassurance I like on small, easy-to-lose tools. I don’t expect to need it—the machining and heat treat inspire confidence—but knowing replacement is on the table makes it easier to throw this socket into a travel kit without babying it.

The bottom line

This DeWalt 4 mm impact socket is a thoughtful piece of kit for miniature metric fasteners. The flank-drive geometry grips small nuts securely, the nose is slim enough for tight cavities, and the standard length gives you control without being stubby. Laser-etched markings are easy to read, retention options are covered, and the finish holds up to regular use.

It’s not a do-everything socket—no 4 mm ever is—and the black oxide will appreciate a bit of care. If you regularly work in the world of M2 hardware, it earns a spot in the front row of your 1/4 in drawer. If you don’t, it’s still a durable, well-executed size that rounds out a metric set without taking up space.

Recommendation: I recommend this socket. It combines precise geometry, compact dimensions, and impact-rated durability in a size where mistakes are costly. Pair it with a fine-tooth 1/4 in ratchet or a low-torque power ratchet, and it will make small-fastener work faster, safer, and less frustrating.