Threaded Screws, Bolts & Nuts

Q: What Is the Difference Between a Screw and a Bolt?

Traditionally, a bolt is a partially or non-threaded cylindrical fastener that is used with a nut to join materials. A screw, on the other hand, is always fully threaded and can be fastened directly into a material without requiring a nut.

Q: How Do I Choose the Right Size Screw or Bolt?

The size depends on the application and the materials being joined. It is important to consider both the diameter and length to ensure a secure and durable connection. A general rule is that the screw length should be at least twice the thickness of the top material being fastened.

Q: What Materials Are Screws and Bolts Made Of, and How Does This Affect Their Use?

Screws and bolts are commonly made from materials such as steel, stainless steel, and brass. The choice of material affects corrosion resistance and strength. For example, stainless steel is ideal for outdoor and humid environments due to its rust resistance.

Q: What Do Strength Classes 4.8, 8.8, and 10.9 Mean?

These numbers indicate the strength rating of the screw or bolt. The first number represents tensile strength in hundreds of megapascals (MPa), while the second number, multiplied by 10, shows the yield strength ratio. For example, 8.8 means a tensile strength of 800 MPa and a yield strength of 640 MPa (80% of 800 MPa).

Q: What Is Thread Pitch, and Why Is It Important?

Thread pitch is the distance between thread peaks on a screw or bolt. It affects how quickly a screw tightens or loosens and how strong the connection is. A finer thread pitch provides a stronger connection but requires more turns to tighten or loosen.

Q: How Do I Know Which Nut Fits My Bolt or Screw?

A nut and bolt or screw must have the same thread size and pitch to fit together. Always check the markings on both the nut and the bolt/screw to ensure compatibility.

Q: What Is the Difference Between Electro-Galvanized and Hot-Dip Galvanized Screws?

Electro-galvanization applies a thin zinc coating through an electrolytic process, providing basic corrosion protection. Hot-dip galvanization, on the other hand, dips the screw in molten zinc, creating a thicker, more durable coating that is better suited for outdoor and harsh environments.

Q: Can I Use the Same Screws for Both Wood and Metal?

No, screws are designed for specific materials. Wood screws have deep threads to grip wood fibers, while machine screws have finer threads designed for metal applications. Using the wrong type may result in weak connections and potential damage.

Q: What Is an Allen Screw, and When Is It Used?

An Allen screw (hex socket screw) has a hexagonal hole in the head and is tightened using an Allen wrench (hex key). It is commonly used in applications where the screw head needs to be flush with or below the surface or where space is limited.

Q: How Can I Prevent a Nut from Loosening Over Time?

To prevent a nut from loosening, you can use: Lock nuts (e.g., nylon-insert lock nuts). Spring washers to increase friction. Thread-locking compounds to create a secure hold These methods help keep the nut in place, even under vibrations or heavy loads.

At Sagro.se, we offer a comprehensive range of fasteners, including threaded screws, bolts, and nuts, designed for various applications and industries. Our selection includes products in different dimensions, materials, and strength classes to meet your specific requirements.

Types of Fasteners

We provide a variety of fasteners to suit your needs:

Hex Bolts: Ideal for robust connections in construction and industry.
Allen Screws: Perfect for applications requiring a smooth exterior appearance.
Flange Bolts: Provide increased surface contact and evenly distribute load.
Carriage Bolts: Commonly used in wood structures to prevent rotation.
Stud Bolts: Suitable for applications requiring a permanent threaded rod.
Threaded Rods: Ideal for custom lengths and specialized applications.
Nuts: Available in various types such as hex nuts, flange nuts, and lock nuts for secure fastening.
Washers: Used to distribute load and protect surfaces when tightening.

Dimensions and Threads

Our range includes fasteners in multiple dimensions and thread types, including:

Metric Threads: M6, M8, M10, M12, M14, M16, M18, M20, M24
Fine Thread Options: M8 x 1.0, M12 x 1.25
UNF Threads: UNF 5/8" -18, UNF 5/16" -24

Materials and Coatings

Our fasteners are made from high-quality materials to ensure durability and corrosion resistance. We offer products in:

Steel
Stainless Steel (A2-70)
Brass

For additional protection, coatings such as electroplating and untreated surfaces are available to suit different applications.

Strength Classes

We offer fasteners in various strength classes to meet different load requirements, including:

4.8
8.8
10.9
A2-70

These classifications help you select the right product for your specific needs, ensuring reliable and secure connections.

Standards and Specifications

Our products meet international standards such as:

DIN 931, DIN 933, DIN 961
DIN 603 (Carriage Bolts)
ASME B18.2.1

These standards guarantee high quality and compatibility with your existing systems and components.

Special Fasteners

In addition to standard fasteners, we offer specialty products such as:

Stud Bolts (DIN 939)
Carriage Bolts (DIN 603)
Allen Screws with Countersunk Head (DIN 7991)

These products are designed for specific applications, giving you flexibility in your projects.

Packaging Options

To make your work easier, we offer fasteners in various packaging sizes:

Small packs of 2 or 4 pieces
Larger boxes with up to 200 or 1000 pieces

This allows you to order the exact quantity needed for your projects, whether small or large.

Order Online Easily

Visit our website to explore our full range of threaded screws, bolts, and nuts. With detailed product descriptions and filtering options, you can quickly find the fasteners that match your needs. We offer fast deliveries and competitive prices to ensure you get the right products on time.