Fastener specification sheets may look technical, but learning how to read them is crucial for engineers, procurement teams, OEM buyers, and project managers. Misinterpreting just one dimension or grade can lead to equipment failures, project delays, and mismatched parts.
This blog explains each part of a fastener datasheet so you can order with confidence—and avoid costly errors.
A fastener specification sheet is a technical document that provides detailed information about a fastener’s design, dimensions, material, mechanical properties, and standards. It helps buyers, engineers, and procurement managers verify that the fastener meets the requirements of their application. When properly understood, a spec sheet acts like a blueprint, reducing errors and ensuring performance and safety in critical operations.
Key elements of a specification sheet include:
1. Product Name and Size
The first line typically includes the fastener type, thread size, and length—for example, “Hex Bolt M10 x 75 mm.” Here, M10 represents the metric thread with a 10 mm nominal diameter, and 75 mm is the length of the bolt, usually excluding the head unless otherwise noted.
2. Material Grade
Materials dictate a fastener’s strength and resistance to corrosion. Common stainless steel grades like SS 304 and SS 316 offer varying levels of corrosion resistance, with SS 316 being the better option for marine or chemical applications. High-tensile grades like 8.8 or 10.9 are preferred in automotive and structural projects, while mild steel is suitable for light-duty or indoor applications.
3. Thread Type and Pitch
The thread type (e.g., metric, UNC, UNF) defines the screw’s compatibility with nuts or tapped holes. Thread pitch indicates the distance between threads and affects the fastening strength. Coarse threads are faster to assemble and better in soft materials, while fine threads are stronger and suitable for high-vibration environments.
4. Head Type and Drive Style
The head style determines the bolt’s fit, load distribution, and appearance. Hex heads are standard for industrial use, socket cap screws are ideal for tight spaces, and countersunk heads sit flush with the surface. Drive styles such as Allen (hex socket), Phillips, slotted, or Torx indicate the type of tool required for installation and vary in torque resistance.
5. Standards Compliance
Reputable fasteners often mention international standards like DIN, ISO, ASTM, or BS. These codes indicate the product’s compliance with globally accepted specifications. For instance, DIN 933 refers to full-threaded hex bolts, while DIN 931 refers to partially threaded ones. ISO 4017 is the international equivalent of DIN 933.
6. Finish or Coating
The coating or finish is crucial for durability, especially in corrosive environments. Zinc-plated fasteners are suited for indoor use, hot dip galvanized (HDG) fasteners resist rust in outdoor settings, and passivated stainless steel enhances corrosion resistance. Specifying the right finish helps maximize the fastener’s service life.
7. Mechanical Properties
Mechanical details such as tensile strength, yield strength, and hardness are critical for load-bearing applications. These values ensure the fastener can withstand the mechanical forces applied during use. For example, a tensile strength of 800 MPa means the fastener can resist significant pulling force without breaking.
8. Certifications and Test Reports
Some spec sheets include details about compliance documents or test certificates. These can include Mill Test Certificates (MTC), NABL-approved lab reports, or third-party inspections, especially for large-scale or export orders.
Let’s decode a common fastener specification:
“Hex Bolt M10 x 75 mm, SS 316, DIN 933, Full Thread, Passivated”
The product is a hexagonal head bolt with a metric thread of 10 mm diameter and 75 mm in length. The material is stainless steel grade 316, which is ideal for marine or chemical exposure. DIN 933 means it’s a fully threaded bolt compliant with German standards. The passivated finish enhances its corrosion resistance by removing surface impurities.
This description gives the supplier everything they need to deliver the right part.
Final Takeaway:
Fastener spec sheets are your blueprint for secure, efficient installations. Once you know how to decode them, you can prevent ordering errors, ensure correct mechanical fit, and confirm compliance with project standards.
Still have questions? Our team at Swastik Industrial Works can help you match specs to the right products.
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