Kadrick Metric Screw Assortment, 2000PCS Metric Bolt Assortment Kit M2 M3 M4 M5 Machine Screws with Lock & Flat Washers, Grade 10.9 Alloy Steel Hex Socket Button Head Black Screws Nuts and Bolts Kit

Why I keep this metric screw kit within arm’s reach

My workbench constantly attracts projects that stall out over one missing fastener. That’s why I’ve been testing the Kadrick metric screw kit as my “house stock” for small machines, electronics, and general repairs. Over a few weeks, I reached for it to button up an electric scooter with a couple of rattly panels, shore up a computer case frame, and knock out a handful of maker projects. It did what a good assortment should do: reduce trips to the hardware store, provide consistent, high-strength hardware, and make it easy to match sizes quickly.

What you actually get

This is a 2000-piece assortment of metric hex-socket button-head machine screws in M2, M3, M4, and M5 sizes, plus matching nuts, flat washers, and lock washers. The lengths cover a sensible spread:

• M2: 4, 8, 12, 16 mm
• M3: 6, 8, 12, 16 mm
• M4: 8, 12, 16, 20 mm
• M5: 8, 12, 16, 20 mm

Threads adhere to standard metric pitches (0.4/0.5/0.7/0.8 mm), and the screws are Grade 10.9 alloy steel in a black finish. In hand, the hardware feels well-made: threads are clean with minimal burrs, the socket recesses are crisp, and the finish is uniform. The manufacturer quotes an average dimensional error under 0.01 mm; while I didn’t mic every part, I saw nothing that fought installation or felt out of spec.

If you tend to work in metric—3D printers, CNC accessories, small appliances, automotive accessories, hobby robotics—this mix hits the common cases well. Button heads give you a lower profile than cap screws without the clearance issues of a pan head, and the included lock washers help in vibration-prone assemblies.

My kit also included a couple of small hex keys and a tiny retrieval magnet. They’re not workshop-grade drivers, but they’re handy for a quick fix when the proper tools are across the room.

Strength and fit: does Grade 10.9 matter here?

For an assortment like this, strength and thread consistency matter more than absolute strength ratings. Still, the Grade 10.9 alloy steel is reassuring. On the scooter panel repair (M5 × 16 with lock washers), I could bring the fastener up to a firm torque without any sense of the socket rounding out or the head deforming. Button-head screws don’t have the same wrenching margin as cap heads—the hex socket is shallower—so good material and clean machining are important. These delivered.

On the computer frame repair, I used M3 hardware through a thin steel bracket with flat washers on both sides. The threads started cleanly, seated square, and didn’t gall. The nuts run smoothly without binding, which tracks with the stated precision.

One practical note: the black finish is almost certainly a black-oxide or similar treatment. It offers mild corrosion resistance at best. Indoors and for most shop tasks, that’s fine. For damp environments, outdoor fixtures, or anything maritime, stainless hardware is still the safer bet. I’d also use anti-seize or a bit of paste wax if mating these to aluminum to reduce the risk of galvanic corrosion and future seizing.

Organization and the case

The kit arrives in a compartmentalized plastic box. Each cell is labeled, and initially everything is tidy. After a week of regular use, I have two observations:

• The box makes it quick to grab common sizes, and labeling cuts down on guesswork.
• The internal dividers in my box are not the most robust. If you press down or flex the lid while fishing out small parts, dividers can shift and let small hardware migrate between compartments. It’s not catastrophic, but it does turn retrieval into a precision game on busy days.

I mitigated it in two ways. First, I decanted the most-used sizes into small, latching parts cups I keep on the bench. Second, I added a strip of tape over a couple of wobbly dividers. If you’re a 3D printing type, a custom tray insert is a great weekend print and solves the problem neatly. The included magnet also helps pluck a single M2 screw without scattering its neighbors.

Everyday usability

A few patterns emerged as I put this kit to work:

• Coverage: The length spread is well chosen. M2 at 4–16 mm is perfect for standoffs, sensors, and small brackets. M3 at 6–16 mm covers most electronics and 3D printer assemblies. M4 and M5 at up to 20 mm reach light machinery and scooter/bike accessories. I seldom felt “I wish there was a 22 or 25 mm” option for the tasks I tackle indoors.
• Washers and lock washers: Flat washers kept thin sheet metal and printed parts from dimpling. The lock washers did their job on the scooter panel and a vibration-prone fan housing. They’re old-school compared to nyloc nuts, but for a general kit they’re absolutely useful.
• Socket quality: The hex recesses are consistent. With proper drivers (2.0/2.5/3.0/4.0 mm hex keys for M2–M5), engagement felt solid. I try to avoid ball-end drivers on first break to reduce cam-out; that habit served me well here.
• Thread quality: No cross-threading scares or swarf in the threads. Nuts spin on smoothly. That sounds basic, but in bargain assortments it’s where corners are often cut.

Limitations worth noting

• Head style: These are button heads only. If your project calls for countersunk (flat head) screws, shoulder bolts, or standard socket cap screws for higher torque, you’ll need a second kit.
• Corrosion: Not stainless. For outdoor or corrosive environments, plan accordingly.
• Case durability: The storage box is serviceable but not shop-tough. If you open and close it dozens of times a week, expect to reinforce or replace it.
• Metric only: Obvious, but worth stating—there’s no imperial hardware. If your shop is mixed, keep an SAE kit nearby to avoid forced fits.

Who this suits best

• Makers, electronics hobbyists, and 3D printer owners who constantly need M2–M5 screws in common lengths.
• Home repair folks who want a one-and-done metric set for appliance panels, brackets, and light fixtures.
• Small shops that want a backup bin for quick turnarounds without pausing to order single-size boxes.

It’s less appropriate for marine work, exterior architectural projects, or heavy machinery where stainless, zinc-plated, or larger-diameter fasteners are the norm—and where head style or thread locking requirements are more specific.

What I’d change

• Upgrade the box. Even a slightly thicker lid and fixed dividers would prevent cross-contamination of sizes.
• Add nyloc nuts for M4/M5. They’d complement the lock washers and expand the vibration-resistant options.
• Consider a small handful of socket cap screws in each size. Button heads are great, but cap heads cover higher-torque needs.

Pros

• Broad, practical spread of M2–M5 lengths with matching nuts, flat washers, and lock washers
• Grade 10.9 alloy steel with crisp hex sockets and clean threads
• Consistent sizing and standardized pitches; parts fit as expected
• Saves real time on small repairs and prototypes
• Good value as a bench-stock kit
• Backed by a two-year after-sales support window

Cons

• Storage case dividers can shift and let parts mingle
• Black-oxide-like finish isn’t ideal for outdoor or corrosive environments
• Button head only; no countersunk or cap head alternatives
• No nyloc nuts in the mix

Recommendation

I recommend the Kadrick metric screw kit as a staple for any bench that sees regular metric projects. The hardware itself is the headline: strong, well-machined, and sized for the jobs that most often stall a repair. The inclusion of matching nuts and both flat and lock washers turns it into a complete fastening system for light to medium-duty tasks. While the case is the weak link, that’s solvable with a better organizer—and it doesn’t detract from the real value, which is having the right fastener on hand when you need it. If your work spans M2–M5 and you favor indoor or shop use, this is a set you’ll reach for again and again.