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Why Add Threads to a Dowel Pin?Understanding the Ingenuity of Internally Threaded Dowel Pins

  • Writer: 翰君 陳
    翰君 陳
  • Oct 30
  • 3 min read

1. What’s the Difference Between a Dowel Pin and an Internally Threaded Dowel Pin?



Internally Threaded Dowel Pin
Internally Threaded Dowel Pin


A common question first: what makes an Internally Threaded Dowel Pin different from a regular dowel pin?








A standard dowel pin is mainly used for positioning and alignment, commonly found in molds, mechanical components, and assembly jigs.The internally threaded dowel pin, however, adds one key feature — a threaded hole inside the center.


This thread isn’t for decoration; it makes the pin smarter.You can screw in a bolt to pull it out, allowing easy disassembly or maintenance even in confined spaces.


In short:

  • Use a standard dowel pin for permanent, one-time assemblies.

  • Use an internally threaded dowel pin when frequent removal or maintenance is needed.


Item

Standard Dowel Pin

Internally Threaded Dowel Pin

Function

Fixing & positioning

Fixing + removable, serviceable

Structure

Solid body, no hole

With internal thread (one or both ends)

Removal Method

Driven or pressed out

Pulled out using a screw

Typical Use

Permanent assembly

Repeated assembly / maintenance

Price

Lower

About 1.3–1.8× higher (depending on threading type)

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2. Material & Structure Differences


The key variations between types of threaded dowel pins depend on thread count, machining depth, and material.


Type

Machining Difficulty

Common Materials

Description

Single-Threaded

Easy

S45C, SUS304, or custom materials

Basic and cost-efficient, most common type

Double-Threaded

Requires threading both ends, precise coaxial alignment

S45C, SUS304, or custom materials

Allows extraction from either side, higher flexibility

Through-Thread (Full Thread)

High precision drilling, longer machining time

SUJ2, SUS304, or custom materials

Ideal for long pins or when bolts must pass through, stronger overall structure

Internally Threaded Dowel Pin
Internally Threaded Dowel Pin



Size Label Example:“Ø4 (M3 Thread)” means:

  • Ø4 → Outer diameter 4 mm, fits into a 4 mm locating hole

  • M3 → Internal thread size for M3 screw insertion/removal









Remember:The hole diameter determines Ø,the removal tool determines M,ensuring solid installation and easy maintenance.


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3. Why Choose Double-Threaded or Through-Thread Types?


Because they make installation more flexible and removal easier.

  • Double-Threaded Type:Threads on both ends allow screws to be inserted from either side for extraction.→ Best for limited-space assemblies or dual-access structures.→ No need to identify which end is threaded during maintenance.

  • Through-Thread Type:The internal hole passes through completely, enabling use of long bolts to fasten two components together.→ Ideal for longer pins or where two parts must be clamped tightly.


In simple terms:

  • Single-Threaded: Standard type – “just enough” for basic applications.

  • Double-Threaded: Enhanced version – easier assembly and maintenance.

  • Through-Thread: Industrial-grade heavy-duty version – for maximum structural strength.

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4. Common Applications


Internally threaded dowel pins are often used in assemblies that require precise alignment but also easy disassembly — especially in systems that undergo regular maintenance or cleaning.


Typical examples include:

  • Mold and jig assemblies: For accurate positioning and alignment every time parts are reinstalled.

  • Automation mechanisms: Used in robotic arms and assembly lines for easy maintenance or part replacement.

  • Equipment frames and housings: To fix structural panels while maintaining removable space.

  • Semiconductor, food, and medical equipment: Common in cleanroom and high-precision environments.


In short — whenever you need high positioning accuracy and smooth disassembly, an internally threaded dowel pin is your best choice.


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5. Key Selection Tips


  • Shaft Diameter: Match the hole size. Typical fit is Hole H7 / Pin h6.

  • Thread Specification: Confirm screw size (e.g., M2–M6) matches your extraction tool.

  • Material Selection:

    • Carbon Steel (S45C): Cost-effective for general machinery.

    • Bearing Steel (SUJ2): High hardness and wear resistance for precision alignment.

    • Stainless Steel (SUS304): Best for corrosion resistance and clean applications.

  • Disassembly Frequency:If frequent removal is expected, choose double-threaded or through-threaded versions.


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6. Why Choose Sheng Fong Precision?


Selecting the right dowel pin isn’t just about size — it’s about precision, consistency, and reliable supply.These are exactly what Sheng Fong Precision (SFP) is known for.

  • Material Diversity: S45C, SUJ2, SUS304, SUS420, and more — to suit various applications.

  • Complete Specifications: Available in single-threaded, double-threaded, and through-thread versions; standard or custom options.

  • Consistent Quality: Every batch is inspected for dimensional accuracy and thread depth to ensure smooth installation.

  • Fast Delivery: Stock available for standard sizes, flexible for urgent or small-quantity orders.

  • Professional Support: We provide technical advice on hole tolerance, thread size, and installation precision.


With SFP’s expertise, your assembly will always stay accurate, serviceable, and reliable.



📩 Contact us on LINE (ID: @s9000) — we’ll help you select the most suitable dowel pin for your application.


🛒 View full specifications: https://lihi3.me/4260L



 
 
 

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