Precision Locating Pins for Modular Fixtures and Repeatable Assembly

When it comes to precision assembly, repeatable fixture design, and error-proof production, few components are as critical—and as underrated—as the Locating Pin.

At Dongguan Sango Hardware Fasteners Co., Ltd., we’ve been manufacturing high-precision locating pins for over 20 years, supporting industries like aerospace, automotive, electronics, and custom automation.

In this article, we break down what locating pins are, how they’re used, and how to choose or customize the perfect type for your application.

1. What Is a Locating Pin?

A Locating Pin is a precision-machined dowel or pin used to position parts accurately during assembly, machining, or inspection.

Installed into jigs, fixtures, or tooling plates, they act as repeatable reference points that ensure the exact placement of components every time.

✅ Functions:

• Define accurate XY positions
• Limit movement in one or more directions
• Prevent misalignment or rotation
• Speed up setup and reduce measurement errors

2. Common Types of Locating Pins

🔹 Straight Locating Pin (Cylindrical)

• Basic form, typically used for slip-fit holes
• Often paired with a diamond pin to prevent over-constraint

🔹 Shoulder Locating Pin

• Has a step (shoulder) to define insertion depth
• Allows consistent seating and prevents pin over-insertion

🔹 Tapered Locating Pin

• Self-centering tip to ease alignment
• Ideal for blind holes or operator-guided insertion

🔹 Diamond Locating Pin

• Oval cross-section to allow movement in one axis
• Common in 2-pin positioning systems to avoid stress buildup

🔹 Ball-Head Locating Pin

• Rounded tip for floating alignments or uneven surfaces
• Used in robotics, sensor brackets, or modular fixturing

3. Where Are Locating Pins Used?

Locating pins are indispensable in:

• 🧰 Workholding jigs and modular fixtures
• 🛠️ Injection mold alignment and core matching
• 📐 CMM inspection setups and gauges
• 🚗 Automotive production lines
• 🧪 PCB fixture plates and test stations
• 🛩️ Aerospace tooling with repeat positioning

They are also critical in lean manufacturing systems where quick changeover and zero-defect goals are prioritized.

4. How to Choose the Right Locating Pin

5. Customization Options from Sango Hardware

• 📏 Size range: Ø2mm ~ Ø20mm (metric & inch)
• 📐 Length tolerance: ±0.01mm available
• 💠 Head styles: round, flat, threaded, pull-ring
• 🌈 Surface finishes: black oxide, nitrided, polished, TiN-coated
• 🔒 Retention types: press-fit, slip-fit, screw-in, keyed

We also provide mating bushings and guide bushings for complete positioning systems.

6. Case Study: Improving Fixture Repeatability with Custom Locating Pins

Client: German automation system integrator
Problem: Existing fixture plates required re-alignment each time they were swapped, slowing down the line

Sango Solution:

• Designed Ø10mm shoulder locating pins + diamond pins, hardened to HRC58
• Added chamfered lead-in and black oxide coating
• Delivered with matching bushing sets

Result:

• Alignment time reduced by 90%
• Pin wear life exceeded 500,000 cycles
• Operator training simplified; no measurement tools required

7. Why Choose Sango Hardware for Locating Pins?

🔩 20+ Years of Machining Experience

Precision dowel and locating pin production using CNC, surface grinding, and heat treatment

🧪 Full Quality Testing

Hardness, roundness, length, surface finish, and tolerance inspections

📐 Custom Designs Supported

Non-standard geometry, logo engraving, anti-rotation flats, and double-shoulder designs available

🌍 Global Export Service

RoHS-compliant, ISO 9001 certified, export to over 30 countries with English documentation

8. Conclusion: Accurate Positioning Begins with Precision Locating Pins

If you want repeatable, operator-proof assembly or machining—start with locating pins that hold up to real-world demands.

Contact Dongguan Sango Hardware Fasteners Co., Ltd. today for standard or custom-made locating pins that deliver precision, durability, and efficiency.