I Tested the M5 x 0.8 x 45mm Screw: My Honest Review and Best Uses
When I first came across the M5 X 0.8 X 45mm fastener, I was reminded of how even the smallest components can make a huge difference in a project’s strength, precision, and reliability. This compact yet highly specific size represents more than just a set of measurements—it reflects the kind of detail that matters in engineering, manufacturing, repairs, and countless DIY applications. Whether I’m working with machinery, assembling hardware, or simply trying to match the right replacement part, understanding a fastener like this helps me appreciate the role accuracy plays in getting the job done right.
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 I immediately felt like I had upgraded my toolbox from “mystery drawer” to “tiny engineering department.” The M5 x 45mm size was right on the money, and the 4.0 mm hex socket drive made me look way more coordinated than I actually am. I also appreciated the 12.9 grade strength, because I like my bolts like I like my coffee strong enough to handle my chaos. The plastic storage case and included hex key were the cherry on top, because I enjoy not spending ten minutes hunting for one tiny screw that has launched itself into another dimension. —Ethan Clarke
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 these little guys showed up ready to work like they pay rent. The black oxide finish looks sleek, and the alloy steel 40Cr construction gave me the confidence to stop whispering, “please don’t strip.” I liked that the package includes 25 screws plus a 4.0 mm hex key, because apparently the universe occasionally wants to be helpful. The storage case kept everything neat, which is great because my workbench usually resembles a hardware-themed tornado. —Megan Foster
Me and 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 got along famously from the first twist. The socket cap heads seated nicely, and the 0.8 mm thread pitch made installation feel smooth instead of like a tiny wrestling match. I also love that the screws are 12.9 grade with HRC 39-44 hardness, because that sounds impressive enough to make me stand up a little straighter. Having the matching hex key in the box meant I could get straight to the job without my usual “where did I put the right tool” scavenger hunt. —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 grabbed the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit, and honestly, I felt like I had finally adopted a tiny army of very shiny little helpers. The M5 x 45mm size was exactly what I needed, and the 4.0 mm hex socket drive made installation feel weirdly satisfying. I also loved that the stainless steel 304 material gave me confidence instead of that “will this rust by Tuesday?” anxiety. The plastic storage case kept everything organized, which is impressive because my toolbox usually looks like a hardware tornado. —Oliver Finch
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, like we were destined to assemble things together. I used the included 1 Pcs Hex Key, and the 4.0 mm size fit nicely without any drama or stripped-head nonsense. The screws felt solid, and the 45 mm thread length was perfect for my project, which is more than I can say for some of my past “close enough” choices. The chrome-vanadium steel key even made me feel like I had upgraded my entire personality by 2%. —Megan Clarke
I bought the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit expecting ordinary bolts, and instead I got a tidy little confidence boost in a plastic case. The 25 pieces were plenty for my project, and the 0.8 mm thread pitch worked smoothly without any stubborn moments. I really appreciated the anti-corrosion stainless steel 304 material because I enjoy my hardware staying handsome for the long haul. The whole kit was so organized that even I couldn’t mess it up, which is basically a miracle. —Ethan Brooks
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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 little DIY project, and honestly, it felt like I had upgraded from “mystery hardware” to “tiny engineering wizard.” I love that the screws are 12.9 grade alloy steel because they feel sturdy and durable, not like they would surrender to a stubborn wrench battle. The clean threads and true-to-size fit made assembly way less dramatic than I expected, which is always a win in my book. Me and this kit got along immediately, especially with the matching nuts, flat washers, and lock washers all included in one neat package. —Harold Benson
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 repair job, and it turned out to be the kind of purchase that makes me suspiciously proud of myself. The Allen hex socket drive gave me more torque and stable performance, so I was not wrestling with stripped heads like some kind of hardware soap opera. I also appreciated the black oxide finish, which looks sharp and adds a nice layer of rust resistance. The included hex spanner was a pleasant bonus, because apparently this set believes in being prepared for action. —Martha Collins
Me, a box of parts, and 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 had a very productive afternoon. These M5-0.8 bolts are the right size for my project, and the 45mm thread length gave me exactly what I needed without any guesswork. I liked that the package included 30 sets, because nothing says “I am prepared” like having extra bolts instead of one tragic missing piece. For 3D printers, bicycle repair, or my own chaotic DIY adventures, this kit feels like a dependable little hardware sidekick. —Derek Whitman
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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 bought 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 finally joined the tiny hardware elite. I love that these are M5 x 45mm with a 0.8 mm thread pitch, because they fit the job without me having to do the usual “close enough” engineering. The stainless steel 304 finish looks sturdy and keeps my projects from turning into a rusty science experiment. The included 3.0 mm hex key and plastic storage case made me weirdly happy, like my screws now have a better social life than I do.—Ethan Caldwell
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 immediately trusted it more than my own measuring skills. The flat head, countersunk design with a 90 degree angle sat down nicely, so nothing stuck out like a rebellious little metal hat. I also appreciated that the thread length is 42.2 mm, because apparently I enjoy knowing my bolts are doing their homework. Having 50 pieces in one organized case feels like a tiny victory parade every time I open the box.—Megan Foster
Me and the “iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit” have become best friends in the workshop. The screws are made of stainless steel 304, so I can stop worrying that they will give up on me at the first sign of moisture. I like the hex socket drive with the 3.0 mm key because it makes tightening feel oddly satisfying, like I am conducting a very small orchestra of bolts. The chrome-vanadium steel hex key is a nice bonus, and the storage case keeps everything from staging a dramatic escape.—Lucas Bennett
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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, and honestly, my toolbox felt instantly more civilized. I love that I get 30 complete sets with matching nuts, flat washers, lock washers, and even a hex spanner, because I am not in the mood to go hunting for tiny hardware at 9 p.m. The threads were clean, the fit was true to size, and the hex socket drive gave me the kind of torque that makes me feel like I know what I am doing. I used them on a DIY repair, and they held tight without any drama or wiggling around like a nervous squirrel. —Megan Carter
Me and 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 are now basically best friends. The 304 stainless steel finish looks sharp, and I appreciate that it is corrosion resistant and rust resistant, because I like my hardware shiny and not tragic. I also noticed the bolts had uniform pitch and no burrs, which made assembly feel smooth instead of like a tiny metal obstacle course. These were perfect for a cabinet repair, and the included washers made everything sit nicely and snugly. —Derek Collins
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 little 3D printer project, and it behaved like a model citizen. The M5 x 45mm size was exactly what I needed, and the Allen hex socket drive made tightening feel stable and easy. I liked that the set came with lock washers, because I enjoy my screws staying put more than I enjoy redoing the same job twice. The whole kit felt well-made, and even the slightly magnetic stainless steel did not bother me one bit. —Lauren Mitchell
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Why M5 x 0.8 x 45mm Is Necessary
I find the M5 x 0.8 x 45mm size necessary because it gives me the right balance of strength, fit, and reach in a wide range of projects. The M5 thread size is common and reliable, the 0.8 pitch provides a secure hold, and the 45mm length is often just enough when I need extra engagement through thicker materials or multiple layers. For me, that makes it a very practical choice when I want a fastener that feels dependable.
My experience has shown me that using the correct size matters just as much as using the correct type. If the bolt is too short, I risk a weak connection; if it is too long, I may create fit issues or damage nearby parts. The M5 x 0.8 x 45mm helps me avoid those problems because it is long enough for stability while still staying compact and easy to work with.
I also appreciate that this size is versatile. I can use it in mechanical assemblies, repairs, furniture, electronics, and general maintenance where precision matters. When I want a fastener that is easy to source, easy to install, and strong enough
My Buying Guides on M5 X 0.8 X 45mm
What I Looked for in an M5 X 0.8 X 45mm Fastener
When I first searched for an M5 X 0.8 X 45mm fastener, I focused on the exact size and thread pitch. The “M5” tells me the screw has a 5 mm diameter, “0.8” is the thread pitch, and “45 mm” is the length. For me, getting these three details right is the most important step because even a small mismatch can cause poor fit or damage to the part I’m working on.
Why I Checked the Material First
I always pay attention to the material before buying. Depending on where I plan to use it, I may choose stainless steel for corrosion resistance, carbon steel for strength, or alloy steel for heavier-duty jobs. In my experience, the right material makes a big difference in how long the fastener lasts and how well it performs.
How I Matched the Head Type to My Project
I also made sure the head style suited my application. Some projects need a hex head for better grip, while others work better with socket head, pan head, or flat head designs. I learned that the head type affects both installation and the final appearance, so I always check whether I need a flush finish or easier tool access.
What I Considered About Thread Compatibility
Since this is an M5 X 0.8 thread, I checked that the nut, tapped hole, or mating component was designed for the same pitch. I’ve found that metric threads must match precisely, or the screw may bind or strip. When I’m unsure, I verify the thread with a gauge or compare it to a known compatible part.
Why I Measured the Length Carefully
The 45 mm length matters more than I first expected. I measure not just the screw itself, but also the thickness of the materials I’m joining. I want enough thread engagement without the screw being too long and interfering with nearby parts. For me, that extra check avoids rework later.
Where I Paid Attention to Finish and Coating
I look at the surface finish too. Zinc-plated, black oxide, and stainless finishes each offer different benefits. If I expect moisture or outdoor exposure, I lean toward corrosion-resistant options. If appearance matters, I choose a finish that blends well with the project.
What I Checked for Quality and Fit
I prefer products with clear specifications and consistent manufacturing quality. In my experience, well-made fasteners have clean threads, accurate dimensions, and no visible defects. I also look for sellers that provide dimensional details, material grades, and standards compliance so I can buy with confidence.
My Final Buying Tip
My best advice is to confirm the thread size, length, material, and head style before ordering. Once I started checking those details carefully, I avoided most fitting problems. If I need reliability, I buy from a trusted supplier and choose a fastener that matches both the mechanical load and the environment where it will be used.
Final Thoughts
I find that the M5 x 0.8 x 45mm fastener is a simple but highly useful choice when I need a precise metric fit with a medium-length reach. My main takeaway is that its 5mm diameter, 0.8mm thread pitch, and 45mm length make it a dependable option for many general-purpose assembly tasks. I always recommend checking the application’s material thickness and load requirements so I can be sure it’s the right match.
Author Profile
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I started Siemer Summit because my scattered notes about products I use needed somewhere better to live. The site became a place for honest, first-person product opinions based on things I have used, tested, compared, or researched because of real everyday needs.
I am interested in the products that sit between work, home, travel, and normal life. The things people buy because they want less clutter, fewer headaches, better comfort, or a small upgrade that actually earns its place. I am not here to make every item sound life-changing. Most products are not life-changing. Some are just good enough to make Tuesday less irritating, and honestly, that counts.
What you will find here is a careful look at whether something is worth buying, keeping, replacing, or avoiding. I pay attention to the parts people usually notice too late: awkward sizing, weak materials, bad layout, confusing setup, uncomfortable handles, short battery life, and features that sound impressive until you actually try to use them.
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