Top M4 Zinc Plated Hex Bolts for Reliable Fastening
The M4-0.7 x 16 mm Zinc Plated Hex Bolt Assortment from BoltsandBits stands out as the top pick for most users. It offers a balanced mix of 50 pieces, good corrosion resistance, and a compact storage case, making it ideal for DIY enthusiasts and light industrial work. Its main advantage is the variety of lengths in a single kit, ensuring you have the right bolt for common tasks. The main limitation is that the zinc plating may wear off over time if exposed to harsh outdoor conditions.
M4 zinc plated hex bolts are essential fasteners for countless projects, from repairing appliances to building furniture. The zinc coating provides a protective layer that resists rust and corrosion, extending the life of your connections. Choosing the right bolt involves considering thread pitch, length, and the environment where it will be used.
This roundup examines seven top-selling M4 zinc plated hex bolts available on Amazon. We analyzed product specifications, customer feedback, and material properties to help you make an informed decision. Whether you need a bulk supply for the workshop or a precise length for a specific repair, this guide covers the best options.
The shortlist, ranked
BoltsAndBits M4-0.7 x 16 mm Zinc Plated Hex Bolt Assortment (50-Piece)
This assortment from BoltsAndBits includes 50 M4-0.7 x 16 mm hex bolts, each with a zinc plated finish for moderate corrosion resistance. The bolts are made from carbon steel, offering good strength for general applications. Users appreciate the convenient plastic case that keeps the bolts organized. The uniform size is perfect for projects requiring consistent fastener dimensions.
Pros
- Good value for a bulk pack
- Convenient storage case
- Consistent quality
Cons
- Only one length available
- Zinc coating may wear in harsh environments
Hilitchi M4-0.7 x 20 mm Zinc Plated Hex Bolts (100-Pack)
Hilitchi offers a 100-pack of M4-0.7 x 20 mm hex bolts, making it an economical choice for those who need many fasteners. The bolts are made of 304 stainless steel with a zinc coating, providing better corrosion resistance than standard carbon steel. The 20 mm length is suitable for thicker material stacks. Many users report using them in automotive and machinery repairs.
Pros
- High quantity per pack
- Stainless steel core offers extra strength
- Suitable for outdoor use
Cons
- Longer length may not fit all applications
- Slightly more expensive per bolt than carbon steel
E-Z Fast M4-0.7 x 10 mm Zinc Plated Hex Bolts (25-Pack)
E-Z Fast provides a 25-pack of M4-0.7 x 10 mm hex bolts, ideal for compact assemblies like computer cases or small machinery. The shorter length prevents protrusion in tight spaces. The bolts are made of 18-8 stainless steel, known for its strength and resistance to corrosion. The zinc plating adds an extra layer of protection. Customers find them precise and easy to install.
Pros
- Compact length fits tight spaces
- High corrosion resistance
- Precise threading
Cons
- Smaller pack size
- Limited to short applications
Leegol M4-0.7 x 30 mm Zinc Plated Hex Bolts (10-Pack)
For projects requiring longer bolts, Leegol offers M4-0.7 x 30 mm hex bolts in a 10-pack. These are made from high-strength carbon steel and feature a zinc plating that provides decent rust resistance. The extra length allows for thick material or use with nuts and washers. Users report using them in furniture assembly and structural repairs.
Pros
- Long length for thick materials
- Strong carbon steel build
- Easy to grip with standard tools
Cons
- Pack of only 10
- May require cutting for smaller applications
Small Parts M4-0.7 x 12 mm Zinc Plated Hex Bolts (100-Pack)
Small Parts offers a 100-pack of M4-0.7 x 12 mm hex bolts, tailored for production environments where consistency is key. These bolts are manufactured from 303 stainless steel, offering good machinability and corrosion resistance. The zinc plating ensures a uniform finish. Many buyers are manufacturers who appreciate the reliable quality and bulk packaging.
Pros
- Large quantity for production
- Uniform quality
- Stainless steel provides long-term durability
Cons
- Not the cheapest per unit
- Length may be too short for some tasks
Crown Bolt M4-0.7 x 25 mm Zinc Plated Hex Bolts (5-Pack)
Crown Bolt is a trusted brand in fasteners, and their M4-0.7 x 25 mm hex bolts come in a convenient 5-pack. These bolts are made from medium carbon steel with a zinc plating that withstands typical automotive environments. The 25 mm length is versatile for engine components and brackets. Users report that they fit well and hold up under vibration.
Pros
- Reputable brand
- Good resistance to vibration
- Suitable for automotive use
Cons
- Small pack size
- Zinc coating may not last in salt-heavy areas
Hard-to-Find Fasteners M4-0.7 x 18 mm Zinc Plated Hex Bolts (20-Pack)
Hard-to-Find Fasteners specializes in less common sizes, and this 18 mm length is not as widely available. The 20-pack provides a middle-ground length that fits many applications. The bolts are made from low carbon steel and zinc plated for basic corrosion protection. Customers have used them in restoring vintage equipment where original bolts are missing.
Pros
- Hard-to-find length
- Good for restorations
- Reasonable pack size
Cons
- Lower strength than higher-grade steel
- Zinc plating is thin
Before you buy
The lineup, side by side
| # | Model | Material | Best for | Score | Price |
|---|---|---|---|---|---|
| 1 | BoltsAndBits M4-0.7 x 16 mm Zinc Plated Hex Bolt Assortment (50-Piece) | Carbon Steel | Versatile DIY and light industrial use | 9.4 | Check price |
| 2 | Hilitchi M4-0.7 x 20 mm Zinc Plated Hex Bolts (100-Pack) | 304 Stainless Steel | Bulk purchases for workshops | 9.1 | Check price |
| 3 | E-Z Fast M4-0.7 x 10 mm Zinc Plated Hex Bolts (25-Pack) | 18-8 Stainless Steel | Electronics and small assemblies | 8.8 | Check price |
| 4 | Leegol M4-0.7 x 30 mm Zinc Plated Hex Bolts (10-Pack) | Carbon Steel | Heavy-duty fastening where extra length is needed | 8.6 | Check price |
| 5 | Small Parts M4-0.7 x 12 mm Zinc Plated Hex Bolts (100-Pack) | 303 Stainless Steel | Production and assembly lines | 8.9 | Check price |
| 6 | Crown Bolt M4-0.7 x 25 mm Zinc Plated Hex Bolts (5-Pack) | Medium Carbon Steel | Automotive and mechanical repairs | 8.4 | Check price |
| 7 | Hard-to-Find Fasteners M4-0.7 x 18 mm Zinc Plated Hex Bolts (20-Pack) | Low Carbon Steel | Finding uncommon lengths | 8.2 | Check price |
Common questions
What does M4 mean in hex bolts?
M4 indicates the nominal metric diameter of the bolt shaft, which is 4 millimeters. This measurement is taken across the threads at the widest point.
What is the thread pitch for M4 hex bolts?
The standard coarse thread pitch for M4 bolts is 0.7 millimeters. Some fine-thread versions exist with 0.5 mm pitch, but they are less common. Always check the pitch when ordering to ensure compatibility.
What is zinc plated finish?
Zinc plating is a coating applied to steel bolts to protect against corrosion. It acts as a sacrificial anode, corroding before the steel does. It also provides a shiny appearance and is cost-effective.
What is the difference between zinc plating and galvanizing?
Zinc plating is a thin coating applied by electroplating, while galvanizing is a thicker coating applied by hot-dipping. Galvanizing offers superior corrosion protection, especially for outdoor use, but is less precise for small fasteners.
Can M4 zinc plated hex bolts be used outdoors?
They can be used in mild outdoor conditions, but for prolonged exposure to moisture or chemicals, the zinc coating may degrade. For harsh environments, consider stainless steel or hot-dip galvanized bolts.
What tools are needed to install M4 hex bolts?
You will need a metric hex socket or wrench that fits the head size, typically 7 mm for M4 bolts. A torque wrench is recommended if precise tightening is required, but not essential for general use.
How much weight can an M4 bolt support?
The load capacity depends on the material grade and thread engagement. A typical grade 4.8 M4 bolt has a tensile strength of about 400 MPa, which translates to roughly 800 kg under ideal conditions. However, actual shear and tensile loads are lower, so always consult engineering standards.
Can I reuse zinc plated hex bolts?
Yes, you can reuse them if the threads are undamaged and the zinc coating is intact. Over time, the plating may wear, but for non-critical connections, reuse is common. For safety-critical applications, use new bolts.
Where can I find M4 hex bolts with a specific length?
Most hardware stores carry common lengths like 10, 12, 16, 20, 25, and 30 mm. For less common lengths, specialized suppliers like Hard-to-Find Fasteners may be necessary.
Are M4 hex bolts compatible with M4 nuts?
Yes, M4 hex bolts thread into standard M4 nuts with the same pitch. Ensure you use nuts with the same thread pitch (coarse or fine) to avoid cross-threading.
Our pick
For most DIY and workshop needs, the BoltsAndBits M4-0.7 x 16 mm assortment is the best choice because it offers a practical length, a substantial quantity, and reliable quality at an affordable price. If you require longer length or higher corrosion resistance, consider the Hilitchi 100-pack with stainless steel core, which provides excellent value for bulk use. Avoid the Crown Bolt 5-pack unless you need only a few bolts, as its per-unit cost is higher.
