Supplier of ISO 7379 Shoulder Bolts and DIN 6921 Flange Bolts. Available in Grades 8.8-12.9 & Stainless Steel (A2/A4) with Full Heat-Lot Traceability.
ISO/DIN High-Strength Bolts Manufacturer: Precision, Anti-Rotation & Structural Fasteners
Engineer robust connections with our certified ISO/DIN industrial bolts. We specialize in application-specific solutions, from ISO 7379 Precision Shoulder Bolts for guiding mechanisms to DIN 603 Anti-Rotation Carriage Bolts. Our inventory supports heavy-duty demands with Alloy Steel and Stainless Steel (A2/A4) options, featuring advanced coatings like Zinc Flake and Geomet for superior corrosion protection. Backed by an ISO 9001 quality system, every order is verifiable with EN 10204 3.1 certification and salt-spray reports. Contact our engineers for custom sizes and bulk pricing.
Standards ISO 12474 / ISO 21269 · ISO 14579 · ISO 7379 · DIN 603 · DIN 6921 · DIN 479
Bolt Types Socket Head (Fine Thread) · Torx Drive · Shoulder · Carriage · Flange · Square Head / Dog Point
Grades 8.8 / 10.9 / 12.9 · Stainless A2/A4 (on request)
Finishes Zinc White Passivation · Thermal Black · Zinc Flake · Geomet · Electropolishing
Materials Carbon Steel · Alloy Steel · Stainless Steel
Docs EN 10204 3.1 · CoC · Heat/Lot Traceability
* ISO 9001 quality system · EN 10204 3.1 available (heat-number traceability) · Dimensional inspection reports on request · Coating / salt-spray reports on request · Samples for verification available
Types of Bolts
Fasteners
Bolts (Structural & External)
Screws (Socket & Precision)
Nuts (Mating Parts)
Washers & Rings
Studs & Anchors
Pins & Plugs
➡ Custom / OEM Fasteners
➡ Standards & Finishes
Fine Thread Socket Head Bolt (ISO 12474/21269)
Socket Head Bolt (Allen)
Torx Drive Socket Head Bolt (ISO 14579)
Hex Head Bolt – Coarse Thread
Hex Head Bolt – Fine Thread
Hex Head Fit Bolt
Precision Shoulder Bolt (ISO 7379)
Carriage Bolt – Square Neck (DIN 603)
Serrated Flange Hex Bolt (DIN 6921)
Square Head Bolt with Collar
Square Head Bolt – Short Dog Point (DIN 479)
Why Choose Our ISO/DIN Standard Bolts?
Real Manufacturing & Quality Control
We produce ISO/DIN standard bolts with controlled processes for thread accuracy, head geometry, and consistent torque performance. Inspection records can be provided by request.
Strict Material Verification
Carbon steel, alloy steel, and stainless steel lots are verified before production. PMI for stainless, chemical composition reports, and heat/lot traceability are available.
Clear Traceability & Documentation
Each shipment can be supplied with EN 10204 3.1, CoC, and heat/lot traceability to support audits and supplier qualification.
Responsive Engineering Support
Not sure which bolt standard fits your assembly? Share your drawing or application details—our team will recommend the correct standard, thread type, grade, and finish.
What Is a Bolt?
A bolt is a threaded fastener designed to clamp parts together, typically used with a nut or a pre-tapped hole. Bolts are specified by standard, size, thread type, grade, and surface finish to ensure fit, strength, and corrosion performance.
Key Characteristics：
Clamping Function: Creates preload to hold parts together under vibration and load.
Specified by Standard: ISO/DIN standards define geometry, tolerances, and performance requirements.
Thread Options: Metric coarse or metric fine (fine thread improves adjustment and resistance to loosening in some assemblies).
Performance Defined by Grade: Common classes include 8.8 / 10.9 / 12.9 and stainless A2/A4 options.
Standards Included in This Bolts Range
| Standard | Bolt Type | Typical Use Case |
|---|---|---|
| ISO 12474 / ISO 21269 | Fine thread socket head bolts (Allen) | Fine adjustment, compact assemblies, serviceability |
| ISO 14579 | Torx drive socket head bolts | Higher drive engagement, reduced cam-out risk |
| ISO 7379 | Precision shoulder bolts | Tooling, motion assemblies, accurate locating |
| DIN 603 | Carriage bolts (square neck) | Anti-rotation fastening in slots/wood/fixtures |
| DIN 6921 | Serrated flange hex bolts | Fast assembly, built-in bearing surface, anti-loosening effect |
| DIN 479 | Square head bolts (short dog point) | Fixture clamping, positioning and repeatable setups |
Coarse vs Fine Thread: How to Choose
Quick rule of thumb: Choose coarse thread for general-purpose assembly and faster installation. Choose fine thread when you need finer adjustment, better preload control in certain assemblies, or improved performance in thin-walled/tapped parts (with sufficient thread engagement).
| Factor | Coarse Thread | Fine Thread |
|---|---|---|
| Assembly speed | Faster | Slightly slower |
| Adjustment precision | Standard | Better |
| Typical use | General machinery | Precision / service assemblies |
| Notes | Good for most applications with proper locking | Requires correct engagement length and matching tapped pitch |
How to Specify a Bolt (RFQ Checklist)
- Standard: ISO/DIN number (e.g., ISO 7379 / DIN 603)
- Size: Diameter × length (e.g., M10 × 40)
- Thread: Coarse or fine (include pitch for fine thread, e.g., M10 × 1.25)
- Grade / Material: 8.8 / 10.9 / 12.9 or stainless A2/A4
- Finish / Coating: zinc, zinc flake, Geomet, thermal black, electropolish, etc.
- Quantity & Delivery: batch size / annual demand / target lead time
- Documents: EN 10204 3.1 / CoC / traceability / coating report (if needed)
Materials, Grades & Surface Finishes
Grades
- 8.8: General high-strength applications
- 10.9: Higher strength for demanding joints
- 12.9: Very high strength for compact designs (confirm coating compatibility)
Materials
- Carbon Steel
- Alloy Steel
- Stainless Steel (A2/A4 on request)
Finishes
- Zinc White Passivation
- Thermal Black
- Zinc Flake / Geomet
- Electropolishing (stainless)
Quality, Inspection & Traceability
- Incoming material control: heat/lot verification; PMI for stainless when required
- In-process checks: thread gauges, head geometry, bearing surface verification
- Mechanical verification: tensile / hardness testing per requirement
- Coating verification: thickness & corrosion reports on request
- Documents: EN 10204 3.1, CoC, and traceability supplied as needed
Common Applications
Tooling & Motion Assemblies
Precision locating and repeatable setups using shoulder bolts and fit bolts.
Anti-Rotation Joints
Square neck carriage bolts for fastening where rotation must be prevented.
Fixture Clamping
Dog point and square head bolts for positioning and clamping in fixtures.
High-Strength Connections
Select grade, finish, and locking method based on load and environment.
FAQ
When should l use fine thread bolts?
You should use Fine Thread Bolts (UNF/Metric Fine) in applications requiring high tensile strength and vibration resistance. Fine threads have a larger tensile stress area and a smaller helix angle compared to coarse threads, which creates a stronger “lock” that prevents loosening in dynamic environments like automotive and aerospace assemblies.
Key Engineering Benefits:
Higher Strength: They have a larger stress area, providing greater load-bearing capacity in tension.
Vibration Resistance: The shallower helical angle increases friction, preventing the bolt from vibrating loose.
Precision Adjustment: Finer pitch allows for more precise torque settings and adjustments.
What is a shoulder bolt used for?
A Shoulder Bolt (also known as a stripper bolt) is a specialized fastener with a precision-ground, unthreaded shaft used as a pivot point, bearing surface, or guide pin. They allow attached parts—such as pulleys, gears, and punch press dies—to rotate or slide freely while the bolt remains securely fastened.
How to Measure (ISO 7379 Standard): When ordering, specify the Shoulder Diameter and Shoulder Length (L).
Critical Rule: Measure the shoulder length from strictly under the head to the start of the threads. Never include the threaded section in the length measurement.
Do you provide traceability documents?
Yes, for critical engineering applications, we provide Material Test Reports (MTRs) in accordance with EN 10204 3.1. Unlike a simple Certificate of Conformance (CoC), an MTR documents the specific Heat Number, chemical composition, and mechanical properties (tensile strength, hardness) of the raw steel used in your exact batch.
Document Types Available:
EN 10204 3.1 (MTR): Verified test data linked to the manufacturing lot (Recommended for structural/pressure applications).
EN 10204 2.1 (CoC): A declaration of compliance with the order specifications without specific test data.
What information do you need to quote bolts quickly?
To provide an accurate quote and avoid manufacturing delays, please include these seven core specifications in your Request for Quote (RFQ): Quantity, Diameter & Thread Pitch, Length, Material Grade, Head Style, Finish, and Certification Requirements.
Measurement Checklist:
Hex/Socket Head Length: Measure from under the head to the tip.
Flat (Countersunk) Head Length: Measure the total length including the head.
Thread Pitch: Specify if you need Coarse (UNC) or Fine (UNF) threads.