Heavy Duty Coiled Spring Pins
SPIROL’s heavy duty Coiled Spring Pins are available in diameters ranging from 1.5mm (.062") up to 20mm (.750"). Standard materials include high carbon steel, 302/304 nickel (austenitic) stainless steel, and 420 chrome (martensitic) stainless steel. Diameters larger than 12mm (.500") are available in 6150 alloy steel.
SPIROL invented the Coiled Spring Pin in 1948. Coiled Pins are available in light duty, standard duty and heavy duty to match the required strength and flexibility for each application. A pin too strong for the applied load will not flex and may damage the hole. A pin that is too flexible may fatigue prematurely within the assembly. The Coiled Pin with the optimal balance of strength, flexibility and diameter will result in the prolonged useful life of the assembly.
Generally, our heavy duty Coiled Spring Pins are recommended for use in hardened materials where design limitations restrict the use of a larger diameter standard duty Coiled Pin.
Application Engineering Assistance: If you would like assistance in selecting the proper diameter and duty Coiled Spring Pin for your assembly, please Request Technical Support! We are here to help!
Shop Our Heavy Duty Coiled Pins: For small quantities, click the Shop Now button below. For larger quantities or custom requests, please Request a Quote and one of our team members will get back to you quickly!
Metric Sizes - Heavy Duty
SPIROL's heavy duty metric Coiled Spring Pins conform to ISO 8748 and ASME B18.8.3M. Ranging in diameter from 1.5mm up to 20mm, these heavy duty Coiled Pins are offered in high carbon steel, 6150 alloy steel (for diameters 16mm and larger), 302/304 nickel (austenitic) stainless steel and 420 chrome (martensitic) stainless steel.
Inch Sizes - Heavy Duty
SPIROL offers inch (imperial) heavy duty Coiled Spring Pins in diameters ranging from .062" (1/16) up to .750" (3/4). Standard materials include high carbon steel, 302/304 austenitic (nickel) stainless steel, and 420 martensitic (chrome) stainless steel; as well as 6150 alloy steel for diameters .625" (5/8) and larger. Heavy duty inch Coiled Pins conform to ASME B18.8.2.
If you are unable to find the heavy duty Coiled Spring Pin in the diameter, length, material, or finish that you require within our standard offering, or if you are unsure what Coiled Pin is most appropriate for your assembly, Request Technical Support from our team and we will help you find the most cost-effective solution for your application.
Installation Technology for Pins
In addition to a comprehensive line of engineered components used for joining and assembly, SPIROL also offers a full range of Pin Installation Equipment designed to facilitate cost-effective and high quality assembly of your products. Our installation solutions range from manual machines to fully automated work cells with statistical process control and error-proofing options. We are the only company of our kind that offers the total integrated solution.
Application Success Stories
Pin Shaft to Knuckle in Manual Transmission Shift Linkage
The designers of a shift linkage assembly for a manual transmission required a pin to fasten a shaft within a knuckle. The pin must allow articulation of the shaft and knuckle without introducing clearance between the components. Clearance would result in lash (or play) in the joint that would be detectable when shifting the high performance luxury vehicle. The pin would be subject to high shear load and fatigue due to torsional loading on the bar.
- SPIROL Engineering recommended a heavy duty Coiled Pin as it provides sufficient flexibility to absorb shock and rapid changes in loading to prevent damage to the holes in the assembly, yet it rigid enough to limit movement and thus providing excellent resistance to fatigue.
- Given that Coiled Spring Pins exert constant radial force against the hole wall, they are self-retaining and therefore do not require any secondary mechanism to remain within the hole.
- Of greatest importance is the fact that lash (or clearance) within the manual transmission assembly was significantly reduced compared to any other fastener that they tested.
Pivot Pin / Axle in Flex Head Ratchet Wrench
The manufacturer of hand tools was experiencing retention issues with a Grooved Pin used as pivot / axle within a flex head ratchet wrench. The wrench carried a lifetime warranty, and the manufacturer was concerned about warranty costs, customer satisfaction and the impact of poor quality on their brand.
- SPIROL Engineering determined that the hole tolerance used by the manufacturer to tune for desired "fit and function" was too large for the inflexible Grooved Pin to absorb. When the hole was at the upper limit of the tolerance, there was a single point of contact between the Grooved Pin and the hole. This did not provide adequate retention and allowed the pin to walk out of the hole.
- A Grooved Pin's diameter is larger than the hole in which it is installed. Since the diameter is not flexible, the Grooved Pin requires displacement of material from either the pin or the hole during installation for retention. The result is a press fit with limited contact between the pin's groove peaks and the hole wall.
- SPIROL Engineering recommended replacing the Grooved Pin with a heavy duty Coiled Spring Pin to maximize interference & retention within the limited available length of engagement.
- On the contrary, a Coiled Spring Pin's pre-installed diameter is also larger than the hole, but rather than displacing material during installation, the Coiled Pin compresses upon itself as it is inserted into the hole. Once fully installed, the pin functions as a spring and tries to recover back towards its original diameter. This provides a constant radial force against the hole wall and thus self-retention of the pin.
- SPIROL's heavy duty Coiled Pin provided adequate strength while maintaining enough flexibility to absorb shock and excessive loading to prevent damage to the hole. This helps ensure proper "fit and function" of the pin within the flex head ratchet assembly throughout the intended life of the product.
Retaining Pin in Nail Gun Assembly
A manufacturer of power tools was experiencing issues installing a Composite Pin into their pneumatic nail gun. They were using a Slotted Pin within a Slotted Pin (aka Composite Pin) to meet the high shear and fatigue requirements of the application. The installion process of installing a pin within another pin was difficult, and it was time-consuming to align the slots 180 degrees to each other. The result was high insertion forces, damaged assemblies and difficulty removing the Slotted Spring Pins for service.
- SPIROL Engineering designed an extra-heavy duty Coiled Spring Pin to meet the high shear strength and other performance requirements of the nail gun assembly.
- Using a single extra heavy duty Coiled Spring Pin versus a Slotted Pin installed into another Slotted Pin simplified the installation process, and the insertion forces of installing the single pin was significantly less than installing the Composite Pin.
- Since Coiled Pins and Slotted Pins have similar recommended hole sizes, no modifications to the assembly components needed to be made to incorporate the recommended pin.
- The use of a Coiled Pin absent a slot also made it possible to easily automate the assembly process.
- By replacing the Slotted Pin within the Slotted Pin with a single extra heavy Coiled Spring Pin, productivity was increased and the total assembled cost of the component was reduced.
Local Design, Global Supply.
SPIROL has Application Engineers throughout the world to assist you in your designs, supported by state-of-the-art manufacturing centers and worldwide stocking facilities to simplify the logistics of delivering your product.
Have a manufacturing issue you can't solve? Our engineering experts love a challenge. Recommending efficient solutions for your application requirements is what we do best. Give us a call or fill out the form below to connect with us!+1 860 774 8571