{"title":"Coiled Spring Pins","description":"\u003ch2\u003eCoiled Spring Pins: Spiral Wound Pins for Precision Fastening\u003c\/h2\u003e\n\n\u003cp\u003eCoiled spring pins, also known as spiral pins or coiled pins, are hollow cylindrical fasteners wound from flat spring steel strip into a spiral configuration. This ingenious design creates a pin that compresses during insertion and exerts constant radial pressure against the hole wall, providing secure retention without the stress concentrations inherent in solid pins. Coiled spring pins have become essential in applications demanding shock absorption, vibration resistance, and repeated assembly cycles.\u003c\/p\u003e\n\n\u003ch3\u003eHow Coiled Spring Pins Work\u003c\/h3\u003e\n\n\u003cp\u003eThe coiled spring pin consists of flat strip material rolled into a spiral with approximately 2.25 coils. When inserted into a properly sized hole, the coils compress inward, reducing the pin's outside diameter. Upon reaching its seated position, the coiled material exerts radial spring force against the hole walls, creating a friction fit that resists axial displacement.\u003c\/p\u003e\n\n\u003cp\u003eUnlike solid pins that rely on an interference fit achieved during manufacturing, coiled spring pins self-adjust to the actual hole diameter within their designed range. This accommodates hole tolerance variations while maintaining consistent retention force. The spiral construction also allows the pin to absorb shock loads by flexing rather than transmitting impact directly through the assembly.\u003c\/p\u003e\n\n\u003ch3\u003eCoiled vs. Slotted Spring Pins\u003c\/h3\u003e\n\n\u003cp\u003eBoth coiled and slotted (roll) pins are hollow spring pins, but they differ significantly:\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCoiled Spring Pins:\u003c\/strong\u003e Multiple coils wound from strip material. Load distributes around the entire circumference. No stress concentration points. Can handle higher shear loads. Better fatigue resistance. More expensive to manufacture. Preferred for demanding applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eSlotted Spring Pins:\u003c\/strong\u003e Single wrap of material with a longitudinal slot. Stress concentrates at slot edges. Lower cost. Adequate for lighter-duty applications. The slot creates a weak point under certain load orientations.\u003c\/p\u003e\n\n\u003cp\u003eFor critical applications involving high shear loads, shock, vibration, or fatigue cycling, coiled spring pins outperform slotted pins. For general-purpose applications where cost matters more than peak performance, slotted pins may suffice.\u003c\/p\u003e\n\n\u003ch3\u003eMaterials and Specifications\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eCarbon Spring Steel:\u003c\/strong\u003e The standard material for most coiled spring pins. High carbon content provides spring temper properties essential for radial force generation. Typical hardness ranges from Rockwell C 44-53. Available with plain finish (oiled), black oxide, or zinc plating.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eStainless Steel:\u003c\/strong\u003e 420 stainless and 302 stainless grades provide corrosion resistance for marine, food processing, and outdoor applications. 302 stainless offers better corrosion resistance; 420 achieves higher hardness through heat treatment.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eBeryllium Copper:\u003c\/strong\u003e Non-sparking and non-magnetic for explosive environments and sensitive electronic applications. Excellent corrosion resistance with good spring properties.\u003c\/p\u003e\n\n\u003cp\u003eCoiled spring pins are manufactured to ISO 8748 (heavy duty) and ISO 8750 (light duty) specifications internationally, with corresponding ASME B18.8.4M standards for metric sizes. Key specifications include nominal diameter, recommended hole size, length, and shear strength ratings.\u003c\/p\u003e\n\n\u003ch3\u003eDuty Ratings\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eStandard Duty:\u003c\/strong\u003e General-purpose pins with typical wall thickness for moderate loads. Suitable for linkages, hinges, and locating applications where shear forces are modest.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHeavy Duty:\u003c\/strong\u003e Thicker wall material provides increased shear strength for demanding applications. Used where pins transmit power, resist high impact loads, or must survive millions of fatigue cycles.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eLight Duty:\u003c\/strong\u003e Thinner wall reduces insertion force and radial pressure. Appropriate for soft materials (aluminum, plastics) or applications requiring easy assembly\/disassembly.\u003c\/p\u003e\n\n\u003ch3\u003eApplications\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eAutomotive Industry:\u003c\/strong\u003e Door hinges, throttle linkages, seat mechanisms, steering columns, and transmission components. Coiled pins handle the vibration and shock inherent in vehicle operation.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAerospace:\u003c\/strong\u003e Control surface linkages, landing gear mechanisms, and flight control assemblies where fatigue resistance and reliability are paramount. Many aerospace applications specify coiled pins over slotted due to superior performance.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAgricultural Equipment:\u003c\/strong\u003e Implement hinges, PTO guards, and control linkages on tractors and farm machinery operating in high-vibration, high-impact environments.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIndustrial Machinery:\u003c\/strong\u003e Conveyor components, packaging equipment, robotic actuators, and automation systems where repeated cycling demands fatigue-resistant fastening.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFirearms:\u003c\/strong\u003e Trigger groups, hammer pins, and action components in firearms commonly use coiled spring pins for their impact resistance and ease of field maintenance.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePower Tools:\u003c\/strong\u003e Handle assemblies, switch mechanisms, and accessory attachments in electric and pneumatic tools.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMedical Devices:\u003c\/strong\u003e Instrument hinges and mechanism components where stainless steel coiled pins provide corrosion resistance and reliable long-term function.\u003c\/p\u003e\n\n\u003ch3\u003eHole Preparation and Installation\u003c\/h3\u003e\n\n\u003cp\u003eProper hole preparation is essential for coiled spring pin performance:\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHole Size:\u003c\/strong\u003e Standard recommendations specify hole diameter equal to the minimum material condition of the nominal pin diameter. For example, a 4mm coiled pin typically uses a 4.0mm drilled and reamed hole. Consult manufacturer tables for specific sizes.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHole Finish:\u003c\/strong\u003e Reamed holes provide the best surface finish and roundness for consistent pin performance. Drilled holes are acceptable but may have slightly reduced retention. Punched holes in sheet metal work for non-critical applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eChamfer:\u003c\/strong\u003e Light chamfers on hole entrances ease pin insertion and prevent edge damage to the coils. Avoid heavy chamfers that reduce engagement length.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eInstallation:\u003c\/strong\u003e Use a flat punch sized to contact the pin evenly across its diameter. Drive pins straight—angled insertion damages coils and reduces retention. Support the workpiece during driving to prevent distortion.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRemoval:\u003c\/strong\u003e Drive pins out using a punch from the opposite side. Unlike interference-fit solid pins, coiled spring pins don't require significant force for removal and can be reused if undamaged.\u003c\/p\u003e\n\n\u003ch3\u003eSelection and Ordering\u003c\/h3\u003e\n\n\u003cp\u003eOur coiled spring pin inventory includes standard duty, heavy duty, and light duty configurations in carbon steel and stainless steel. We stock metric and inch sizes in common lengths with custom lengths available for production orders. Specify duty rating based on your application's load requirements—when in doubt, heavy duty provides a safety margin at modest cost increase.\u003c\/p\u003e","products":[],"url":"https:\/\/www.ecomfasteners.com\/collections\/pins-coiled-spring-pins.oembed","provider":"Ecom Fasteners","version":"1.0","type":"link"}