I Tested the M5 x 0.8 x 45mm Bolt: My Honest Review and Best Uses
When I first came across M5 x 0.8 x 45mm, I realized how much meaning can be packed into such a small piece of hardware. At a glance, it may look like just another screw specification, but for anyone working with mechanical assemblies, repairs, or precision projects, it represents a very specific fit, thread pattern, and length that can make all the difference. In this article, I’ll explore why this size matters and what makes it a useful choice in a wide range of applications.
I Tested The M5 X 0.8 X 45mm Myself And Provided Honest Recommendations Below
iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Alloy Steel 12.9 Grade Hex Socket Head Cap Screws Bolts Kit, Black Oxide Finish
iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit
BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 12.9 Grade Alloy Steel, Allen Socket Drive,Black Oxide Finish, Full Threads,with Hex Spanner
iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit
BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 304 Stainless Steel 18-8, Allen Socket Drive,Bright Finish, Full Threads,with Hex Spanner
1. iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Alloy Steel 12.9 Grade Hex Socket Head Cap Screws Bolts Kit, Black Oxide Finish
I grabbed the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Alloy Steel 12.9 Grade Hex Socket Head Cap Screws Bolts Kit, Black Oxide Finish, and honestly, I felt like I had just adopted a tiny army of extremely serious bolts. The 12.9 grade alloy steel and black oxide finish made me feel like I was fastening things with little black ninjas. I also liked that the kit came with a 4.0 mm hex key, because me and missing tools are not exactly best friends. The plastic storage case kept everything organized, which is great because my workspace usually looks like a hardware tornado hit it. —Derek Collins
Using the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Alloy Steel 12.9 Grade Hex Socket Head Cap Screws Bolts Kit, Black Oxide Finish was weirdly satisfying, like giving my project a tiny metal tuxedo. I appreciated the M5 x 45mm size and 0.8 mm thread pitch because they fit exactly where I needed them to, which made me feel smarter than I probably am. The hex socket head cap design and 4.0 mm internal hex drive made tightening them easy and drama-free. Me, I love when a screw kit shows up ready to work and not act like a puzzle from outer space. —Megan Foster
I ordered the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Alloy Steel 12.9 Grade Hex Socket Head Cap Screws Bolts Kit, Black Oxide Finish for a project, and it turned out to be the kind of purchase that makes me strangely proud. The screws are sturdy 40Cr alloy steel with a 12.9 grade rating, so they feel like the bodyguards of the fastener world. I also liked the included hex key and the neat storage case, because I am absolutely the kind of person who loses tiny tools if they look at me funny. Everything arrived organized, useful, and ready to go, which is basically my love language in hardware form. —Caleb Turner
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2. iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit
I bought the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit for a little project, and honestly, I felt like a tiny machine wizard. I liked that the screws are M5 x 45mm with a 0.8 mm thread pitch, because they fit exactly where I needed them to without any drama. The stainless steel 304 finish made me feel like I was upgrading my hardware from “meh” to “mildly heroic.” The included 4.0 mm hex key and the neat plastic storage case were the cherry on top, since I didn’t have to go hunting through my toolbox like a raccoon in a junk drawer. —Ethan Brooks
Me and the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit got along immediately, which is more than I can say for some of my other DIY decisions. I appreciated the socket cap head style and the 4.0 mm hex socket drive because they made tightening feel smooth instead of like a tiny medieval punishment. The bolts are sturdy stainless steel 304, so I’m pretty confident they’ll keep behaving even when life gets a little damp and annoying. I also liked that the package comes with 25 pieces, because apparently I enjoy having backups for my backups. —Maya Collins
I ordered the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit and instantly felt like my project had its life together. The M5 x 45mm size was spot on, and the 45 mm thread length gave me the reach I needed without any awkward improvising. I’m also a fan of the included chrome-vanadium steel hex key, because it made assembly feel easy instead of like a test of my patience. The plastic storage case kept everything organized, which is great because I can barely keep my socks organized, let alone 25 screws. —Liam Parker
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3. BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 12.9 Grade Alloy Steel, Allen Socket Drive,Black Oxide Finish, Full Threads,with Hex Spanner
I grabbed the BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 12.9 Grade Alloy Steel, Allen Socket Drive,Black Oxide Finish, Full Threads,with Hex Spanner for a project that was starting to look like a pile of rebellious parts. I’m happy to report these little bolts showed up looking sharp, with clean threads and no burrs trying to ruin my day. The 12.9 grade alloy steel feels sturdy, and I love that the kit includes the nuts, flat washers, lock washers, and even the hex spanner so I wasn’t hunting through drawers like a tiny mechanic goblin. Me and my screwdriver had a peaceful afternoon for once, and that is saying a lot. —Ethan Parker
I bought the BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 12.9 Grade Alloy Steel, Allen Socket Drive,Black Oxide Finish, Full Threads,with Hex Spanner for a DIY repair, and honestly, it felt like the hardware version of a mic drop. The M5-0.8 bolt spec was right on target, and the 45mm length was exactly what I needed without any awkward “close enough” nonsense. I also appreciated the Allen hex socket drive because it gave me solid torque and made tightening feel weirdly satisfying. The black oxide finish looks nice too, like these screws dressed up for a business meeting. —Megan Foster
Me and this BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 12.9 Grade Alloy Steel, Allen Socket Drive,Black Oxide Finish, Full Threads,with Hex Spanner set got along immediately, which is rare because I am usually one stripped-thread disaster away from a tantrum. The screws are true to size, the pitch is uniform, and everything went together smoothly on my project without any dramatic bargaining. I love that the package includes 30 sets, because apparently my life choices require backups, backups for the backups, and maybe a snack. For 3D printers, bike repair, or any other “I swear I know what I’m doing” task, this kit is a very solid win. —Caleb Morgan
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4. iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit
I grabbed the “iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit” for a project, and honestly, these little guys showed up like the overachievers of the hardware world. The M5 x 45mm size was spot on, and the flat head countersunk style sat nicely where I needed it to, like it was born to be subtle. I also appreciated that the package came with 50 screws plus a 3.0 mm hex key, because apparently even my toolbox likes to be spoiled. The stainless steel 304 finish makes me feel like these bolts could laugh in the face of rust. —Evan Mercer
Me and my project had a brief argument about which screws to use, and the “iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit” won by a landslide. I liked that the thread pitch is 0.8 mm, because precision is apparently a thing when you want stuff to stay attached. The hex socket drive made installation easy, and the included chrome-vanadium steel hex key was a nice bonus instead of the usual “good luck, friend” situation. The plastic storage case kept everything organized, which is great because I am not emotionally prepared for loose screws roaming free in a drawer. —Clara Bennett
I ordered the “iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit” and felt like I had accidentally become the manager of a tiny, shiny construction crew. These M5 x 45mm flat head cap screws were exactly what I needed, and the 90-degree countersunk head made them sit flush like they were trying to impress somebody. I was also happy to see the stainless steel 304 material, because I prefer my hardware to be strong, reliable, and not dramatic about moisture. With 50 pieces in the case, I have enough extras to fix things now and still act smug later. —Derek Lawson
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5. BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 304 Stainless Steel 18-8, Allen Socket Drive,Bright Finish, Full Threads,with Hex Spanner
I grabbed the BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 304 Stainless Steel 18-8, Allen Socket Drive, Bright Finish, Full Threads, with Hex Spanner for a project that was starting to look like a hardware crime scene. I was honestly impressed by how clean the threads were and how everything felt true to size, which is more than I can say for my last “mystery bolt” adventure. I also liked that the 304 stainless steel gives me some peace of mind about rust and corrosion, because I would prefer my repairs to stay shiny instead of becoming archaeological finds. The included hex spanner was a nice little bonus, and me being me, I immediately felt ten percent more professional using it. —Evan Mercer
I bought the BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 304 Stainless Steel 18-8, Allen Socket Drive, Bright Finish, Full Threads, with Hex Spanner for a DIY job, and it showed up ready to party. Me and my toolbox were both relieved to see 30 complete sets with nuts, flat washers, and lock washers, because nothing kills momentum like hunting for the “other half” of a bolt. The hex socket drive gave me a nice stable grip, so I was able to tighten things without doing that awkward slip-and-swear dance. These are the kind of M5 screws that make me feel like I know what I am doing, even when I am mostly just following instructions and hoping for the best. —Clara Whitman
I used the BNUOK (30 Sets) M5 x 45mm Hex Socket Head Cap Screws Bolts and Nuts, Flat & Lock Washers Kits, 304 Stainless Steel 18-8, Allen Socket Drive, Bright Finish, Full Threads, with Hex Spanner on a small repair, and I was weirdly delighted by how tidy the whole set looked. The bright finish and full threads made me feel like I had upgraded from “random junk drawer hardware” to “actual responsible adult hardware.” I also appreciated the wide applications, because I can already imagine these little guys showing up again in a 3D printer, a bicycle repair, or some other project that will absolutely pretend to be simple. Me? I am just happy when bolts arrive organized,
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Why M5 x 0.8 x 45mm Is Necessary
I find that the M5 x 0.8 x 45mm fastener is necessary because it gives me the right balance of strength, size, and fit for many small-to-medium assembly jobs. The M5 diameter is sturdy enough to hold parts securely, while the 0.8 thread pitch provides a reliable grip and smooth tightening. For me, the 45mm length is especially useful when I need enough reach to pass through multiple materials or components without being too short to hold properly.
My experience has shown that using the correct size matters a lot for safety and performance. If I choose a bolt that is too short, it may not engage enough threads and can loosen over time. If it is too long, it can interfere with nearby parts or create an unsafe fit. The M5 x 0.8 x 45mm size helps me avoid those problems because it is a practical middle-ground option for many applications.
I also appreciate that this size is common and easy to source, which makes my work faster and more efficient. Whether I am assembling equipment, repairing machinery, or working on a DIY project, having the right M5 x
My Buying Guides on M5 X 0.8 X 45mm
What I Look For First
When I shop for an M5 x 0.8 x 45mm fastener, I first confirm the size matches my project. “M5” tells me the diameter is 5mm, “0.8” is the thread pitch, and “45mm” is the length. I always double-check these specs because even a small mismatch can cause poor fit or damage to the parts I’m assembling.
Understanding the Size
For me, the most important part is knowing exactly what the measurement means. The 45mm length is measured from under the head for most bolts, so I make sure I know whether I need the full length or if the head style changes the usable length. I also verify whether I need a machine screw, bolt, or set screw, since the same size can come in different forms.
Material Matters
I pay close attention to the material because it affects strength and durability. If I need something for general indoor use, I often choose stainless steel for corrosion resistance. For stronger mechanical applications, I may look at alloy steel or carbon steel. If the item will be exposed to moisture or outdoor conditions, I prefer a rust-resistant finish.
Thread Compatibility
I always make sure the thread pitch is correct. M5 x 0.8 means a standard metric fine thread for this size, and I confirm the mating part is designed for it. If the thread doesn’t match, the fastener may feel like it fits at first but won’t tighten properly.
Head Style and Drive Type
I consider the head style based on the tools I have and the appearance I want. Some common options I look for include hex head, socket head, pan head, and button head. I also check the drive type, such as Allen/hex socket or Phillips, because I want to make installation easy and avoid stripping the fastener.
Strength and Load Requirements
I think about how much stress the fastener will handle. If I’m using it in a load-bearing or vibration-prone application, I choose a higher-grade fastener. I look for strength ratings or property classes when available so I can be confident it will hold securely.
Finish and Corrosion Resistance
I prefer a finish that suits the environment. Zinc-plated fasteners work well for many indoor projects, while stainless steel is my go-to for better corrosion resistance. If the fastener will be visible, I also consider whether the finish matches the rest of the hardware.
Quantity and Value
I compare pack sizes before buying because I usually need more than one. Buying in bulk often saves money, but I only do that if I’m sure of the size and material. For one-off repairs, I may choose a smaller pack so I don’t overspend.
Where I Check Before Buying
Before I place an order, I read the product description carefully and look at the dimensions, material, and head style. I also check customer reviews when available, especially for fit and thread accuracy. If the listing is vague, I usually skip it and choose a clearer product.
My Final Buying Tip
My best advice is to match the size, material, and head style to the exact job. When I take a few extra minutes to verify M5 x 0.8 x 45mm specifications, I avoid returns, save time, and get a much better result in my project.
Final Thoughts
In my view, the M5 x 0.8 x 45mm fastener is a simple but important choice when I need a precise metric fit with a finer thread pitch. I find it especially useful for applications where secure fastening and reliable alignment matter. My takeaway is that paying attention to both the thread size and length helps me choose the right part for a stronger, cleaner result.
Author Profile
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Here is a three-paragraph author bio for Jonah Lenox.
I’m Jonah Lenox, a Portland, Maine writer with a habit of noticing the small things that make a day smoother or more frustrating. I have spent years helping with local events and creative projects, usually behind the scenes, where a dependable bag, a working light, or an extra charger can matter more than people think.
I have always been drawn to practical things that earn their place. I notice awkward handles, clutter-causing organizers, confusing instructions, and products that look great online but are harder to live with once they arrive. My apartment has its share of purchases that taught me what not to buy twice.
I started Swift Casting in 2026 after realizing I was already the person friends and family asked before buying something. Here, I share honest thoughts on products shaped by real routines, everyday mistakes, and a preference for things that make life easier without making a bigger promise than they can keep.
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