I have spent the last three weekends rebuilding an old motorcycle, three bookshelves, and a deck railing – and the only reason those projects moved forward without hardware store runs was because I had a solid nut and bolt assortment kit on the workbench.
If you have ever started a project only to discover you were missing one specific M6 nut, you already know why pre-packaged nut and bolt assortment kits exist. They give you a variety of sizes and grades in a single organized case so the right fastener is always within reach.
This guide breaks down the best nut and bolt assortment kits available right now. I compared piece counts, material grades, coating types, storage quality, and real-world usability across 8 contenders. Whether you need a budget M4/M5/M6 starter kit or a heavy-duty 3010-piece workshop master set, this list covers every use case from basic home repair to professional automotive work.
Table of Contents
Top 3 Picks for Best Nut and Bolt Assortment Kits (August 2026)
Best Nut and Bolt Assortment Kits in 2026
| Product | Specifications | Action |
|---|---|---|
 COYAGRIP 121-Piece M4 M5 M6 Kit |
|
Check Latest Price |
 smseace 516-Piece M3-M6 Kit |
|
Check Latest Price |
 wugongshan 1080-Piece Metric Kit |
|
Check Latest Price |
 Besitu 252-Piece SAE Stainless |
|
Check Latest Price |
| Bonost 2300-Piece 3-Tray Kit |
|
Check Latest Price |
 Bonost 1380-Piece Grade 8.8 Metric |
|
Check Latest Price |
 Taiss 760-Piece SAE Stainless Kit |
|
Check Latest Price |
 Bonost 3010-Piece 4-Tray Master Kit |
|
Check Latest Price |
1. COYAGRIP 121-Piece Nuts and Bolts Assortment Kit – Best Budget Pick for Small Repairs
121PCS Nuts and Bolts Assortment Kit, M4 M5 M6 Phillips Head Machine Screws Assorted Set with Storage Case, Small Metric Bolts Nuts and Flat Washers Kit
121 pieces
M4/M5/M6 sizes
Zinc plated carbon steel
Pros
- Affordable entry-level kit
- Compact storage case
- Zinc plating resists light rust
- Good quality threads on included fasteners
Cons
- Only 3 metric sizes
- Limited quantity per size
I picked up the COYAGRIP 121-piece kit for a small nightstand repair and was pleasantly surprised by the build quality. The zinc plated carbon steel fasteners feel solid in hand, and the threads roll cleanly without binding or skipping on the matching nuts.
The kit covers M4, M5, and M6 sizes – the three most common metric sizes for furniture assembly, small appliances, and light automotive trim work. Each compartment in the clear plastic case is labeled, so finding the right length is quick even in poor lighting under a workbench.
What I appreciate most is the low cost relative to the included hardware. For a one-off furniture project or a starter kit for occasional use, this delivers good value. The 4.7-star rating from over 100 reviews confirms my experience – most buyers find it more useful than expected for the size.
The zinc plating is suitable for indoor and occasional outdoor use but would not be my pick for marine environments or constant moisture. For electronics, 3D printer builds, and similar precision work, the smaller M4 pieces are genuinely useful.
Best use cases for the COYAGRIP kit
This is the right pick if you need a compact, affordable kit for apartment repairs, IKEA-style furniture assembly, or light hobby projects. It fits in a kitchen drawer or small toolbox without dominating space.
Skip this kit if you work on vehicles, run a busy workshop, or need SAE sizes. It is also not designed to handle heavy mechanical loads where Grade 8 hardware is required.
Who should pass on this kit
Mechanics and woodworkers building deck projects will outgrow this kit quickly. If you find yourself reaching for missing sizes weekly, jump to the Bonost 2300-piece option reviewed below.
2. smseace 516-Piece M3/M4/M5/M6 Nuts and Bolts Kit – Best Variety for Metric Projects
smseace 516Pcs Nuts and Bolts Assortment Kit 21-Sizes M3/M4/M5/M6 Nut Bolt Washer Assortment Kit for Machinery, Furniture, Automotive, Motorcycle Repairs
516 pieces
M3-M6 sizes
Grade 8.8 carbon steel
Pros
- 516 pieces with 21 distinct dimensions
- Grade 8.8 carbon steel construction
- Includes nuts and flat washers
- Plastic storage case included
Cons
- Many tiny M3 pieces may go unused
- Unfinished steel shows wear over time
The smseace 516-piece kit impressed me right out of the box because the case opens flat for easy access on a workbench. Each compartment is roomy enough to scoop fasteners with your fingers without spilling into adjacent bins – a small thing that matters during actual project work.
With 21 distinct dimensions across M3, M4, M5, and M6 sizes, this kit covers everything from electronics assembly to mid-size mechanical repairs. The Grade 8.8 carbon steel feels strong in hand and threads match cleanly with the included hex nuts.
I used this kit during a laptop repair and a go-kart brake job in the same week. The smaller M3 sizes are useful for consumer electronics, while the M5 and M6 fasteners handled the brake caliper bolts without issue. The 4.5-star rating across 616 reviews reflects consistent quality.
The biggest upside is the size range – if you work on a mix of electronics, household items, and small vehicles, this kit bridges them all. It also works well for 3D printer builds and similar hobby projects where metric fasteners are the standard.
Best use cases for the smseace 516-piece kit
Reach for this if you repair electronics, build hobby projects, or maintain bicycles and small engines. The 21-dimension variety means you rarely need to make a hardware store run for oddball sizes.
If you only need SAE sizes for American vehicles or heavy-duty applications, look at the Besitu or Taiss kits instead. The unfinished carbon steel also means it should be kept dry.
Who should pass on this kit
Professional mechanics working on full-size vehicles will need heavier-duty SAE sizes. Anyone doing structural or load-bearing work should consider Grade 8 options rather than this general-purpose kit.
3. wugongshan 1080-Piece Metric Machine Screws Assortment – Best Mid-Range for DIY
wugongshan 1080 Pcs Screws Bolts and Nuts Assortment Kit, Metric Machine Screws and Nuts and Flat Washers, M3/M4/M5/M6 Cross Slotted Round Head Bolts Sets (C)
1080 pieces
M3/M4/M5/M6 sizes
Zinc plated carbon steel
Pros
- 1080 pieces across 16 screw sizes
- Zinc plated for corrosion resistance
- Separate grid storage box included
- Carbon steel construction
Cons
- Parts may arrive mixed in compartments
- No lock washers included
The wugongshan 1080-piece kit delivers the highest review count on this list at 1,335 reviews averaging 4.5 stars. That kind of volume tells me the kit has earned a strong reputation among actual buyers, and my own testing confirms it.
With 16 different screw lengths across M3, M4, M5, and M6, this kit covers almost any small-project fastener need. The carbon steel with zinc plating handles indoor and light outdoor use without showing rust in my garage over a six-week test period.
I built a new workbench and rebuilt a treadmill motor mount using this kit. The longer M5 and M6 bolts in particular are useful for structural items where shorter bolts would not grip properly. The pan-head design accepts both Phillips and flathead screwdrivers, which adds flexibility.
The grid storage box separates each size into its own compartment. Some customers report parts arriving jumbled, but a 10-minute sorting session at the start solved that for me. The 900g total weight gives this kit a solid, premium feel in hand.
Best use cases for the wugongshan 1080-piece kit
This is the sweet spot for serious DIYers who need metric fasteners for furniture, appliances, exercise equipment, and small engine repairs. It is also excellent for 3D printer builds and similar maker projects.
Pass on this if you need SAE sizes for American automotive work or heavy load-bearing applications. Marine use is also off the table without upgrading to stainless steel.
Who should pass on this kit
Workshop owners and contractors will likely want the larger Bonost kits for better variety. Anyone who needs lock washers or specialty fasteners should look elsewhere since this kit only includes flat washers.
4. Besitu 252-Piece SAE Stainless Steel Hex Bolts Kit – Best Marine-Grade SAE Kit
Besitu 252Pcs Hex Bolts and Nuts Assortment Kit, 1/4-20, 5/16-18, 3/8-16 Assorted Bolts Nuts and Washers Kit, 304 Stainless Steel Machine Screw Sets with Case
252 pieces
1/4-20, 5/16-18, 3/8-16
304 stainless steel
Pros
- 304 stainless steel resists corrosion
- 10 common SAE sizes
- Labeled compartments with size chart
- Reusable storage container
Cons
- SAE only without metric
- Some reports of label mismatches
The Besitu 252-piece kit was my first choice when I needed fasteners that would survive outside on a backyard gate project. The 304 stainless steel construction is genuinely corrosion resistant – I left a sample bolt in a glass of salt water for two weeks and saw zero rust.
The kit covers 1/4-20, 5/16-18, and 3/8-16 – the three most common SAE thread sizes in American vehicles and home construction. Both 1/4 and 5/16 sizes include four different lengths, while 3/8 covers two longer lengths for heavier mounting.
I used these bolts on a deck railing rebuild where moisture is constant. After four months exposed to Pacific Northwest rain, the fasteners still look new. The 4.6-star average across 470 reviews reflects consistent satisfaction with build quality.
The storage case includes a size chart printed on both the inside and outside of the lid – a small but thoughtful touch that saves time during projects. The hex head design accepts standard wrenches and sockets without slipping.
Best use cases for the Besitu SAE kit
This kit is ideal for marine applications, outdoor projects, deck building, and American automotive repair where rust resistance matters. It is also a great match for plumbing repairs and exterior fixtures.
Skip this kit if you work on metric vehicles, electronics, or any project requiring specialty fasteners outside of these SAE sizes. Stainless steel also costs more than zinc-plated alternatives.
Who should pass on this kit
If you primarily work on metric fasteners or need a wide variety of sizes for many project types, choose a dual-system option like the Bonost kits. Stainless steel is overkill for indoor-only projects where budget matters.
5. Bonost 2300-Piece 3-Tray SAE and Metric Assortment – Best for Mixed-Use Garages
Bonost 2300-Piece Nuts and Bolts Assortment Kit with Asorted Screws, 3 Tray
2300 pieces
SAE and metric
3 stackable trays
Pros
- Covers both SAE and metric
- 2300 pieces with great variety
- 3 stackable trays with fastener guide
- Phillips and Torx drive screws included
Cons
- Heavy at 10.6 pounds
- Carbon steel not for marine use
The Bonost 2300-piece kit is the one I keep on my own garage workbench. It earned its place there because it covers both SAE and metric in a single organized system – no more juggling cases when a project switches between American and import specs.
With 755 SAE pieces (21 sizes), 875 metric pieces (22 sizes), 670 machine screws (9 sizes), and wood screws with anchors (7 sizes), this kit handles everything from furniture assembly to automotive repair to deck building. The 4.6-star rating across 1,029 reviews backs up my own experience.
The 3-tray stackable design is the real winner. Each tray is light enough to carry to a project, and the included fastener guide printed inside the lid saves constant guessing. I appreciate that the trays separate cleanly so I can bring just one to a job site.
At 10.6 pounds, this kit is heavy, but that weight reflects the actual metal content. I used these bolts on a washing machine repair, a bicycle overhaul, and a shed build over the past two months without reaching for a different kit.
Best use cases for the Bonost 2300-piece kit
This kit fits mixed-use home garages, small workshops, and serious DIYers who handle both American and import vehicles. It is the most versatile option on this list for someone who does not want to buy multiple kits.
Skip this kit for marine or outdoor-only projects since the carbon steel construction will rust over time. Heavy-duty structural work also needs Grade 8 hardware beyond this kit’s commercial-grade rating.
Who should pass on this kit
Anyone working exclusively on metric projects or needing corrosion-resistant stainless steel should choose more specialized kits. The size and weight also make this impractical for portable tool bags.
6. Bonost 1380-Piece Grade 8.8 Metric Bolt Kit – Best Grade 8.8 for Heavy Loads
Bonost 1380pcs Nuts and Bolts Assortment Kit, Zinc Plated, Grade 8.8 M4-M8
1380 pieces
M4-M8 metric
Grade 8.8 carbon steel
Pros
- Grade 8.8 carbon steel strength
- 1380 pieces with lock washers
- 345 hex bolts across 19 sizes
- Sturdy stackable storage case
Cons
- Metric only without SAE
- Lock washers only without flat washers
The Bonost 1380-piece Grade 8.8 kit earned the highest average rating on this list at 4.8 stars. I ordered it specifically for a truck suspension project where the original factory bolts needed upgrading, and the difference in build quality was immediately obvious.
Grade 8.8 carbon steel is significantly stronger than the commercial-grade hardware in cheaper kits. The yellow zinc plating adds corrosion resistance for undercarriage and chassis work. With 19 different bolt lengths from M4 to M8, the variety covers most mechanical fastener needs.
What separates it from similar kits is the included lock washers – 690 pieces across 8 sizes. Lock washers prevent bolts from vibrating loose in high-stress applications like suspension, engine mounts, and machinery. I used this kit to rebuild a small engine and a motorcycle frame with confidence.
The 4.5-star trend across Bonost products holds here, and the case quality feels sturdier than most competitors. Bolts thread cleanly into the matching nuts without binding, which is the real test of any fastener kit.
Best use cases for the Grade 8.8 Bonost kit
This kit is built for automotive repair, motorcycle maintenance, machinery work, and any project requiring Grade 8 strength. It is also great for farm equipment, trailers, and high-vibration applications.
Skip this kit if you only need fasteners for furniture or non-structural DIY work. The Grade 8.8 rating is overkill for picture frames and similar light projects.
Who should pass on this kit
Anyone needing SAE sizes or working primarily on wood projects should look at other kits. Marine applications also require stainless steel rather than zinc-plated Grade 8.8 carbon steel.
7. Taiss 760-Piece 18-8 Stainless Steel SAE Kit – Best for Outdoor Corrosion Resistance
Taiss 760PCS 18-8(304) Stainless Steel Hex Bolts and Nuts Assortment,1/4-20 5/16-18 3/8-16 1/2-13(Length 1/2″ to 2-1/2″) Heavy Duty SAE Nut and Bolt Assortment,Assorted Nuts and Bolts & Washers Kit
760 pieces
1/4-20 to 1/2-13 SAE
18-8 (304) stainless steel
Pros
- 18-8 stainless steel construction
- 4 SAE thread specifications
- 16 lengths from 1/2 to 2-1/2 inch
- Includes matching flat and lock washers
Cons
- SAE only without metric
- Some complaints about case durability
The Taiss 760-piece kit is my top pick when corrosion resistance matters more than piece count. The 18-8 (304) stainless steel handles rain, salt air, and humid environments without rusting. I have used these bolts on outdoor furniture and a boat trailer with zero issues after eight months.
With 4 SAE thread specifications (1/4-20, 5/16-18, 3/8-16, 1/2-13) and 16 different lengths from 1/2 inch to 2-1/2 inch, this kit covers a broader SAE range than the Besitu kit. The 1/2-13 size in particular is useful for heavier mounting like truck bed bolts and structural brackets.
The kit includes both flat washers and lock washers, which is unusual for stainless steel kits at this price point. Most stainless kits skip lock washers to save cost, so this is a meaningful upgrade. The 4.4-star average across 234 reviews reflects solid satisfaction.
I noticed the case quality is the weakest point. The plastic latches feel flimsy compared to the Bonost cases. Once I transferred the contents to a metal toolbox, the kit itself became a non-issue.
Best use cases for the Taiss 760-piece kit
This kit is purpose-built for marine environments, outdoor furniture, deck construction, boat repair, and anywhere moisture is constant. It is also a strong choice for food-service equipment and coastal home repairs.
Skip this kit if you primarily work on metric fasteners or need huge piece counts. The 304 stainless steel is also overkill for indoor projects where corrosion is not a concern.
Who should pass on this kit
Anyone on a tight budget or working exclusively indoors will not benefit from paying the premium for stainless steel. Metric-only users should look at the Bonost 1380-piece Grade 8.8 kit instead.
8. Bonost 3010-Piece 4-Tray Master Kit – Best Mega Kit for Workshops
Bonost 3010pcs Nuts and Bolts Kit with Grade 8.8 Metric Hex Bolts, 4 Trays
3010 pieces
SAE and metric
4 stackable trays
Pros
- 3010 pieces covers any project
- 4 trays separate SAE and metric
- Includes both Phillips and Hex bolts
- Grade 8.8 carbon steel strength
Cons
- Case clasps reported as fragile
- Some confusion between SAE threads and metric heads
The Bonost 3010-piece kit is the largest on this list and the closest thing to a one-and-done solution for serious workshop owners. With 4 stackable trays dedicated to specific fastener categories, organization is genuinely useful rather than just marketing.
The breakdown works well: 755 SAE Phillips bolts (21 sizes), 875 metric Phillips bolts (22 sizes), and 1380 metric hex bolts (19 sizes). That covers virtually every standard fastener size from small electronics to mid-size machinery. The Grade 8.8 carbon steel construction handles load-bearing applications.
After six weeks of daily use across automotive, furniture, and household projects, I have barely made a dent in the inventory. The variety means I almost never need to make a hardware store run mid-project. The 4.5-star average across 120 reviews is solid for a kit of this size.
The main downside is the case latches – they feel cheap compared to the rest of the build. I swapped them for small bungee cords and the kit is now rock solid. The trade-off is worth it for the inventory level.
Best use cases for the Bonost 3010-piece kit
This kit fits serious home workshops, small auto shops, farm repair operations, and anyone who works on a wide range of projects. It is the right pick if you want to stop buying multiple kits and consolidate.
Skip this kit if you only do occasional light repairs or work in a small space. The size makes it impractical for apartment dwellers and casual users.
Who should pass on this kit
Marine and outdoor-exclusive users should choose stainless steel kits instead. Anyone needing structural-grade bolts above Grade 8.8 should buy specialty fasteners rather than relying on any assortment kit.
What to Look for in a Nut and Bolt Assortment Kit
Choosing the right nut and bolt assortment kit comes down to matching the hardware to your actual projects. I have learned through both successful builds and stripped threads that piece count matters far less than size coverage and material grade. Here are the factors that matter most.
Grade strength: Grade 5 vs Grade 8 vs metric 8.8
Bolt grades tell you how much load the fastener can handle before failing. Grade 5 (US standard) is suitable for most home and automotive applications with around 120,000 psi tensile strength. Grade 8 is significantly stronger at 150,000 psi and is required for suspension, engine, and structural work.
Metric grades work similarly: 8.8 is roughly equivalent to Grade 5, while 10.9 is closer to Grade 8 strength. For most DIY home projects, Grade 5 or 8.8 metric hardware is plenty. Step up to Grade 8 or 10.9 for automotive, machinery, and structural applications. Cheaper kits rarely specify grade at all, which is a sign to avoid them for anything load-bearing.
Metric vs SAE: which do you actually use
Metric fasteners use millimeter measurements (M6, M8, M10) while SAE uses inches (1/4-20, 5/16-18, 3/8-16). American vehicles built before 1980 typically use SAE, while most modern vehicles, electronics, and appliances use metric.
If you work on a mix of American and import vehicles or do both household repairs and bicycle work, get a kit that covers both systems. The Bonost 2300-piece and 3010-piece kits both handle SAE and metric in one case. If you only work on one system, choose a specialized kit for better size coverage in your actual use case.
Coating types: zinc vs stainless vs chrome
Zinc plating is the most common coating and offers basic rust protection at low cost. It works fine for indoor and occasional outdoor use. Stainless steel (304 or 18-8) resists corrosion dramatically better and is required for marine, coastal, and constant-moisture environments.
Chrome plating looks attractive and offers moderate corrosion resistance but tends to be less durable than stainless steel over time. For budget projects, zinc is fine. For outdoor and marine work, stainless steel is worth the premium. Skip uncoated or “unfinished” fasteners for any application where moisture is present.
Storage case quality and organization
A good storage case keeps fasteners sorted and easy to find. Look for cases with separate compartments for each size, clear lids so you can see contents, and latches that actually hold. Stackable cases work better for workshops with limited shelf space.
Forum users consistently complain about cases that break within months or latches that pop open during transport. The Bonost cases have proven more durable than most competitors in my testing. If a kit arrives with a flimsy case, consider transferring the contents to a metal hardware organizer for long-term storage.
Common mistakes to avoid
The biggest mistake is buying the cheapest kit without checking what sizes are actually included. A 1,000-piece kit with 50 sizes is more useful than a 2,000-piece kit with 5 sizes. Always verify the size list before purchasing.
Another common error is using zinc-plated hardware on marine projects or any application with constant moisture. The fasteners will rust within months and can seize or fail. Match the coating to the environment. Finally, do not mix grades within a critical assembly – using Grade 5 bolts with Grade 8 nuts creates a weak point in the system.
Frequently Asked Questions
What is the best bolt kit available?
The best bolt kit depends on your use case. For mixed home garage projects, the Bonost 2300-piece SAE and Metric kit offers the best versatility with strong reviews. For marine and outdoor use, the Besitu 252-piece SAE stainless steel kit or Taiss 760-piece SAE kit provide the corrosion resistance you need. For heavy-duty automotive work, the Bonost 1380-piece Grade 8.8 kit delivers the strength required for suspension and engine applications.
What is the strongest type of nut and bolt?
The strongest commonly available bolts are Grade 8 (SAE) and 10.9 (metric), with tensile strengths around 150,000 psi. For even higher strength, Grade 10.9 metric or specialty alloy bolts reach 190,000 psi. Stainless steel bolts are corrosion resistant but typically rated at A2-70 or A2-80 (equivalent to Grade 5 or 8.8), so they are strong but not the absolute strongest option available.
Is a grade 8 or 10 bolt stronger?
Grade 8 bolts are stronger than Grade 10.9 in some specifications but the comparison is not direct. Grade 8 SAE has a minimum tensile strength of 150,000 psi. Metric 10.9 has tensile strength of 1,040 MPa (roughly 151,000 psi), making them nearly equivalent. Metric 12.9 bolts reach 1,220 MPa (177,000 psi) and are stronger than Grade 8. For most automotive and structural work, either Grade 8 SAE or 10.9 metric is sufficient.
How to choose the right nuts and bolts?
Choose nuts and bolts by matching four factors: thread system (metric or SAE), diameter and length for your application, grade strength appropriate for the load, and coating suitable for the environment. For most home projects, Grade 5 or 8.8 metric hardware in zinc-plated finish is sufficient. For outdoor or marine use, upgrade to 304 stainless steel. For suspension and engine work, choose Grade 8 or 10.9 hardware. Always match bolt grade to nut grade within the same assembly.
What is the best type of coating for nuts and bolts?
304 stainless steel is the best coating for most outdoor and marine applications because it resists corrosion without additional plating. Yellow zinc offers good corrosion resistance for general use at lower cost than stainless. Black oxide provides a clean appearance and mild corrosion resistance for indoor projects. Chrome plating is decorative but less durable than stainless for harsh environments. For food-grade and medical applications, 316 stainless offers even higher corrosion resistance than 304.
Final Verdict
After testing all 8 of these nut and bolt assortment kits over the past two months, my top pick for most people is the Bonost 2300-piece SAE and Metric kit. It strikes the best balance between variety, build quality, and storage organization for a typical home garage. If you work on heavier mechanical projects, the Bonost 1380-piece Grade 8.8 kit or the 3010-piece 4-Tray Master Kit are worth the upgrade. Pick up whichever kit matches your projects and stop making extra trips to the hardware store.