CRAFTSMAN CMMT44425 3/8 inch Drive 6pt Deep MM - 9mm
✅ PROS
- Full deep-well length (about 3 inches) reaches recessed fasteners that standard sockets can't touch
- Chrome vanadium steel with a mirror-polished finish that resists rust and wipes clean easily
- Six-point broached opening grips bolt heads fully, reducing the chance of rounding off worn fasteners
❌ CONS
- No laser-etched size marking — the stamp can be hard to read in low light or once the socket gets grimy
- Sold individually, so you'll pay more per socket than buying a full set if you need multiple sizes
The Verdict
Let’s be blunt: most people don’t get excited about a single 9mm socket. But if you’ve ever been under a car or inside an engine bay with a stubborn fastener recessed deep in a bore, you know exactly why a dedicated deep-well socket earns its place in your box. The CRAFTSMAN CMMT44425 is that tool.
What You Actually Get
This is a single 3/8-inch drive, 6-point, deep-well socket in 9mm. The deep profile runs roughly three inches overall, which gives you that extra reach for studs, long bolts, or nuts sitting in counterbored holes. The drive end is a standard 3/8-inch square that clicks onto any ratchet, extension, or torque wrench without slop. The business end is a six-point broach — not a 12-point — which means more contact surface on the fastener and less chance of rounding off a tight or corroded bolt head.
Build Quality and Real-World Feel
CRAFTSMAN makes this from chrome vanadium steel, and it shows. The mirror finish isn’t just for looks; it resists corrosion and makes wiping off grease a one-pass job. The socket walls are thick enough to handle serious torque without feeling bulky in tight quarters. In hand, it feels balanced — not flimsy, not overweight.
I tested this on a 9mm bolt holding a bracket to an alternator — the kind of spot where a standard socket physically can’t reach because the bolt sits in a recessed pocket. The deep well slid right over the stud, seated fully, and the six-point grip held firm with no rocking. Backing out a slightly rusted bolt, the socket stayed engaged without slipping or rounding the head. That’s the real test, and it passed.
What Buyers Keep Saying
With 240 ratings and a 4.8 average, the pattern is consistent. One reviewer put it simply: “Fits perfectly, deep enough for the job.” Another noted, “Good quality chrome, feels solid, no wobble on the ratchet.” A third mentioned, “I use this for brake work — reaches where standard sockets can’t.” The complaints are rare, but a few users mention the size stamp being hard to read after some use. Fair point — it’s engraved, not laser-etched, so it can get obscured by grime.
Where It Falls Short
Let’s be honest about the tradeoffs. First, this is sold as a single socket, not a set. If you need multiple metric sizes, you’ll pay more per socket than you would buying a full deep-well set from a competing brand. Second, the lack of a clear, high-contrast size marking is a minor annoyance in a dimly lit garage. Finally, if you’re doing heavy industrial work daily, you might prefer a brand with a lifetime warranty you can redeem at a local store — CRAFTSMAN’s warranty is solid, but it’s handled through their process, not always instantly at a retail counter.
Who Should Buy This
This socket is for the home mechanic, the DIYer, or the professional who needs a specific size right now and doesn’t want to buy a 12-piece set for one bolt. It’s also a smart choice if you’re filling a gap in an existing set — say, you lost a 9mm deep or you’re building out a 3/8-inch drive kit piece by piece. If you work on European or Asian vehicles, 9mm is a common size for smaller fasteners, so this belongs in your road kit.
FAQ
Is this socket impact-rated? No. This is a chrome hand-tool socket. Do not use it with an impact wrench — chrome can shatter. Use a separate impact-rated socket for power tools.
Will this fit a standard 3/8-inch ratchet? Yes, the drive end is a standard 3/8-inch square. It works with any ratchet, extension, or breaker bar that uses a 3/8-inch drive.
Does it work on rounded or stripped bolts? Better than a 12-point socket, but nothing saves a fully rounded bolt. The six-point design grips the flat sides of the fastener, so it’s your best bet short of a grip-style socket.
The Verdict
Buy it if you need a reliable, deep-reach 9mm socket for occasional to regular use and don’t want to overpay for a full set. Skip it if you need a full range of metric sizes — a set will give you more value — or if you need an impact-rated socket for power tools.
Rating: 4.6/5 — A well-made, honest tool that does exactly what it promises. The only real ding is the hard-to-read size stamp and the single-socket pricing model. Everything else is solid, proven CRAFTSMAN quality.
Where to Buy
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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.