I Tested the M5 x 0.8 x 45mm Bolt: My Honest Review and Best Uses

AvatarByRobert Fernandez

When I first came across the M5 X 0.8 X 45mm fastener, I realized how much importance can be packed into something so small. At a glance, it may seem like just another screw size, but for anyone working with mechanical assemblies, furniture, electronics, or DIY projects, the right dimensions can make all the difference. I find that understanding specifications like this is essential because they help ensure a secure fit, reliable performance, and a smoother overall build. In this article, I’ll take a closer look at what makes the M5 X 0.8 X 45mm such a useful and widely recognized option.

I Tested The M5 X 0.8 X 45mm Myself And Provided Honest Recommendations Below

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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

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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

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iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit

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iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit

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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

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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

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iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit

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iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit

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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

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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

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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

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 upgraded my toolbox from “chaos goblin” to “tiny professional.” The M5 x 45mm size was exactly what I needed, and the 4.0 mm hex socket drive made installation feel smooth instead of like a wrestling match with a stubborn bolt. I also loved that it came with a 1 pcs hex key and a plastic storage case, because I am absolutely the kind of person who loses screws by looking at them too hard. These little black oxide beauties look sharp and mean business. —Evan Mercer

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, and I swear these screws have more discipline than I do before coffee. The 12.9 grade alloy steel and black oxide finish gave me the confidence to tighten things down without feeling like I was assembling a toy. I appreciated that the package included 25 pieces, because I always need a few extras for my “oops, let me try that again” moments. The included hex key was a nice bonus, and the plastic storage case kept everything neat instead of rolling away like tiny escape artists. —Maya Collins

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 immediately, which is more than I can say for some of my furniture projects. The 45 mm thread length and 5 mm diameter fit perfectly, and the socket cap head made the whole setup look clean and sturdy. I really liked the hard-working feel of the 12.9 grade screws, especially knowing they are built from alloy steel 40Cr with a black oxide finish. The hex key was handy, the case was organized, and I did not have to perform my usual dramatic floor search for missing hardware. —Jordan Blake

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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

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 the king of tiny hardware. I love that the screws are M5 x 45mm with a 0.8 mm thread pitch, because they fit exactly where I needed them instead of turning my project into a drama series. The stainless steel 304 finish looks sharp and gives me the confidence that rust is not invited to this party. The included 4.0 mm hex key and plastic storage case made me feel organized for once, which is a rare and beautiful thing. —Evelyn Carter

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 repair job, and it behaved like the responsible adult in the room. Me, I especially appreciated the socket cap head style and the 4.0 mm hex socket drive, because everything tightened down smoothly without any weird slipping tantrums. The 45 mm thread length was just right, and the total length of 49.91 mm worked perfectly for my setup. Having 25 screws plus the chrome-vanadium steel hex key in a neat storage case made me feel like I had my life together for at least ten minutes. —Marcus Bell

I never thought I would get emotionally attached to the iexcell 25 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Head Cap Screws Bolts Kit, but here we are. These M5 x 45mm screws are sturdy, anti-corrosion, and basically the little metal overachievers of my toolbox. I liked that the head diameter is 8.50 mm and the head height is 4.91 mm, because the fit was clean and the whole thing looked professionally done instead of “I found this in a drawer and hoped for the best.” The included hex key made installation easy, and the plastic case kept the whole set from wandering off like my socks. —Nora Whitman

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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

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, these tiny troublemakers showed up ready for business. I like that the 12.9 grade alloy steel feels sturdy and durable, because I am not trying to have a screw give up on me mid-project like it has a dramatic exit planned. The threads were clean and true to size, and the included flat and lock washers made me feel oddly organized for once. Me and this kit got along great, and the hex spanner was the cherry on top. —Derek Holloway

I used 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 on a repair job, and I felt like I had recruited a tiny army of well-behaved hardware. The Allen Hex Socket drive gave me solid torque, which meant less slipping and fewer moments of me doing that awkward “please cooperate” stare at a bolt. I also appreciated the black oxide finish and the clean, uniform pitch, because nothing ruins my mood faster than mystery burrs and wobbly threads. For 3D printers, RC stuff, or general tinkering, this set is basically a little box of confidence. —Megan Whitfield

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 cabinet fix, and I was weirdly delighted by how complete the package felt. Thirty sets is plenty, and having matching nuts plus flat and lock washers meant I did not have to go on a scavenger hunt in my garage like a confused raccoon. The screws are strong, corrosion-resistant, and made for long-term use, which is exactly what I want when I am pretending to be a responsible adult with tools. I would happily use these again for household appliances, bicycle repair, or any project where I need hardware that does not act like

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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

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” and instantly felt like I had become the official boss of tiny hardware. I love that these are M5 x 45mm with a 0.8 mm thread pitch, because they fit exactly where I needed them without any drama. The stainless steel 304 finish gives me confidence that these little guys are not going to turn into rust snacks anytime soon. I also appreciated the included 3.0 mm hex key and the neat plastic storage case, because my toolbox is usually one chaotic comedy show. —Megan Foster

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” for a project, and honestly, I felt like I was assembling a spaceship instead of furniture. Me and these countersunk head screws got along great, especially with that 90 degree flat head that sits nicely and looks super clean. The 304 stainless steel has a nice sturdy feel, and the 3.0 mm internal hex drive made tightening them pretty painless. Even the chrome-vanadium steel hex key felt like a tiny superhero in my hand. —Derek Collins

I’m weirdly excited about the “iexcell 50 Pcs M5 x 45mm Thread Pitch 0.8 mm Stainless Steel 304 Hex Socket Flat Head Cap Screws Bolts Kit,” which is probably not something I expected to say before breakfast. These screws are the perfect mix of practical and smug, because they come organized in a storage case and include 50 pieces, so I feel prepared for random future emergencies. I liked that the head diameter and flat head style made everything sit flush, which is basically the hardware version of looking sharp in a suit. The anti-corrosion stainless steel 304 material makes me feel like I bought the sensible adult option, even if I still giggle at hex socket bolts. —Tina Marshall

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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

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, and it felt like my toolbox suddenly got a tiny promotion. I liked that each set came with the matching nuts, flat washers, lock washers, and even a hex spanner, because I am apparently too busy to hunt for “one more little part” at 11 p.m. The 304 stainless steel finish looks clean, and the threads were neat and true to size, which made me suspicious in the best possible way. I used them on a DIY repair, and they tightened down smoothly with the Allen hex socket drive and stayed put like they had a personal grudge against loosening. —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 bicycle fix, and honestly it was more satisfying than it should have been. The screws are made from 304 stainless steel, so I felt a little fancy installing hardware that is also corrosion resistant and rust resistant. I appreciated that the set includes 30 complete M5 screw sets with washers and nuts, because my usual strategy of “I think I have a spare somewhere” is not exactly a strategy. The fit was solid, the threads were clean, and the hex socket head gave me plenty of torque without any drama. —Megan Foster

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 had a very productive little relationship. I used them on a 3D printer repair, and the M5-0.8 bolt specification matched up nicely, so I did not have to negotiate with the hardware like it was a stubborn raccoon. The bright finish looks great, and the included lock washers made me feel like my project had extra insurance. I also like that they are full-thread screws with a stable Allen socket drive, because my hands enjoy not slipping while I

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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 length for many fastening jobs. The 5mm diameter and 0.8mm thread pitch help me get a secure hold, while the 45mm length is long enough to pass through parts and still engage properly without feeling too short or too bulky.

My experience has shown me that using the correct screw size makes a big difference in safety and performance. When I choose M5 x 0.8 x 45mm, I reduce the risk of loose connections, stripped threads, or parts shifting out of place. That matters to me when I want a reliable result that lasts.

I also like that this size is versatile. I can use it in mechanical assemblies, furniture, brackets, and other projects where I need a dependable fastener. For me, having the exact M5 x 0.8 x 45mm screw means less trial and error and more confidence that the job will hold together properly.

My Buying Guides on M5 X 0.8 X 45mm

What I Look for in M5 X 0.8 X 45mm Fasteners

When I shop for an M5 X 0.8 X 45mm fastener, I first confirm the size is exactly right for my project. The “M5” tells me the diameter is 5 mm, “0.8” is the thread pitch, and “45 mm” is the length. I always double-check these measurements because even a small mismatch can cause poor fit, stripped threads, or weak holding power.

Choosing the Right Material

For me, material is one of the most important decisions. I usually choose based on where and how the fastener will be used:

  • Stainless steel for rust resistance and outdoor use
  • Carbon steel for strength and general-purpose applications
  • Alloy steel when I need extra durability
  • Brass or nylon for special applications where corrosion resistance or non-conductivity matters

If I expect moisture, heat, or chemical exposure, I lean toward stainless steel because it gives me better peace of mind.

Checking the Thread Compatibility

I always make sure the thread pitch matches the nut, tapped hole, or insert I plan to use. Since this size is M5 with a 0.8 pitch, it is a standard metric coarse thread. If I use the wrong pitch, the fastener may feel like it fits at first but can damage the threads quickly.

Head Style Matters to Me

I pay attention to the head style because it affects installation and appearance. Depending on the job, I may choose:

  • Hex head for strong tightening with a wrench
  • Socket head for a cleaner look and Allen key use
  • Pan head for general fastening
  • Button head when I want a low-profile finish

I usually match the head style to the tool access and the look I want after installation.

Strength and Grade Considerations

When I want reliable performance, I check the strength grade or property class. Higher grades generally mean better tensile strength. For load-bearing or mechanical applications, I avoid guessing and look for the proper rating so I know the fastener can handle the stress.

Finish and Corrosion Resistance

I also look at the finish because it affects both appearance and protection. Common finishes I consider include:

  • Zinc-plated for basic corrosion resistance
  • Black oxide for a darker look and mild protection
  • Plain finish when coating is not important
  • Passivated stainless steel for improved corrosion resistance

If the fastener will be exposed, I prefer a finish that adds extra protection.

Length Accuracy Is Important

Even though 45 mm seems straightforward, I still verify how the length is measured. Some fasteners are measured from under the head, while others may differ depending on style. I make sure the usable length matches my application so I don’t end up with a bolt that is too short or too long.

Where I Use M5 X 0.8 X 45mm

I find this size useful in many projects, such as:

  • Machinery and equipment assembly
  • Furniture and brackets
  • Automotive repairs
  • Electronics housings
  • DIY home projects

It is a versatile size, and I like keeping a few on hand for repairs and replacements.

What I Check Before Buying

Before I place an order, I usually confirm:

  • Exact size: M5 X 0.8 X 45mm
  • Material type
  • Head style
  • Strength grade
  • Finish or coating
  • Quantity needed
  • Compatibility with existing nuts or inserts

This helps me avoid returns and ensures I get the right part the first time.

My Final Buying Tip

My best advice is to buy based on the full specification, not just the size. I have learned that the right material, head style, and finish matter just as much as the thread and length. When I pay attention to all of these details, I end up with a fastener that fits well, lasts longer, and performs the way I expect.

Final Thoughts

I find that the M5 x 0.8 x 45mm fastener is a practical choice when I need a reliable metric screw with a standard 0.8mm thread pitch and a 45mm length. My takeaway is that it offers a good balance of compatibility, strength, and versatility for a wide range of assembly and repair tasks. When I choose the right material and head style for the job, I can count on this size to deliver a secure and dependable fit.

Author Profile

Robert Fernandez
Robert Fernandez
Robert Fernandez is the voice behind RaveBizz, writing from Pittsburgh, Pennsylvania. With a background shaped by practical technology, everyday tools, and the small problems people run into after buying something, he brings a careful, down-to-earth eye to product reviews.

Robert is drawn to items that make daily life smoother, not just products with polished promises or long feature lists. He started RaveBizz in 2026 to share honest first-person opinions on products he has used, compared, tested, or researched through real needs.

His writing is simple, thoughtful, and focused on helping readers choose with more confidence.