FAQs

SPIROL's standard Coiled Spring Pins, Slotted Spring Pins, Solid Pins, Dowel Bushings, Spring Dowels, Ground Hollow Dowels, Compression Limiters and Inserts for Plastics manufactured from aluminium, brass, carbon steel and stainless steel meet the requirements of Directives 2011/65/EC and 2015/863 Restriction of Hazardous Substances (RoHS),Directive 2000/53/EC End-of-Life Vehicles (ELV), and (EC 1907/2006) Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH).

View SPIROL's full Environmental Compliance Statement

We recommended starting with a temperature 50˚F (28˚C ) above the initial softening temperature for the plastic in question. For plastics with fillers, this initial differential should be increased to around 150˚F (83˚C). Pressure is Insert-size dependent and should be as low as possible in the 5 to 15 PSI (0.03 to 0.10 Mpa) range. The pressure should be just enough to push the Insert into the hole as the plastic melts.

Technically you can use a soldering iron to install Inserts, but it is MOST DEFINITELY not a good idea. You won’t get a repeatable insertion depth, you will likely not install the Insert straight into the hole, and you will not have control over pressure. Also, many soldering irons are not available with a variable temperature setting.

The only way to verify Insert performance is to test the assembly. This is a destructive test. Section the plastic component with the installed Insert in half then remove the sectioned Insert out of the hole and ensure that the features of the Insert are mirrored in the plastic. It is extremely important to ensure proper plastic flow into the features of the Insert as this dictates the torque and pull-out performance. If the plastic did not sufficiently flow into the retention features, the result will be lower Insert performance. SPIROL's Inserts for Plastics Design Guide offers more detailed information about this.

Despite the cost of steel typically being less expensive than brass or aluminium, it is more difficult to machine and steel chews through tooling quicker than brass and aluminium. ALSO, steel Inserts typically require some kind of plating for corrosion resistance which further increases the cost of the Insert and the potential of quality defects due to plating a threaded part – not to mention the potential of mixed product due to the plating process.

This is impossible to answer without testing in your actual assembly. The following factors affect performance:

• Insert type, design within type & quality of features
  
• Plastic specifications
  
• Design & quality of the plastic components including hole tolerance & consistency
  
• The installation process and quality thereof

In addition, there are so many different types of plastics and fillers (and percentage and orientation of those fillers within the plastics) coupled with the complexity of component design makes it impossible to provide Insert performance data which can be applied to specific applications.

SPIROL provides a section in our Inserts for Plastics Design Guide that displays the performance of various style Inserts installed into Nylon 6/6 without fillers in drilled versus moulded holes. The performance data is provided as a comparative guide between Insert types -> not to provide the actual performance that will be achieved in a specific application. For this, you will need to test!

You can calculate the compression that the Limiter needs to withstand provided that you have the bolt size and grade or class. It is also important to use the bolt seating formula to make sure that you are always getting contact between the bolt flange, Compression Limiter and mating component. We do find that sometimes designers forget to account for positional tolerances particularly when multiple bolts and Limiters are used in an assembly. SPIROL offers complimentary Applications Engineering and we stand ready to review your application and help you determine the best Compression Limiter for your requirements. After that, we recommend testing the assembly in the worst case conditions to verify all of your calculations.

It mostly boils down to whether there is a concern with galvanic corrosion. If the joint can not be sealed from exposure to an electrolyte, review the galvanic potential between the metals in the bolted area. This is pretty much the only reason we would recommend a brass over an aluminium Limiter. The aluminium is lightweight (1/3 the weight of brass), lead free and stronger than brass such that you can achieve the same strength in a smaller diameter.

Yes, we can manufacture Compression Limiters in lengths other than what is offered as standard. However, special lengths require an application review to ensure feasibility. Special length Compresion Limiters require a special set up, and often require special material buys, which can drive up costs and minimum order values.

In short, yes. SPIROL offers butted seam Spacers in both SP100 Standard Wall and SP150 Heavy Wall to suit specific application requirements. Butted seam SP100 Standard Wall Spacers are approximately 25% to 30% weaker in columnar strength than welded or DOM tubing in the same material and wall thickness. SPIROL's SP150 Heavy Wall Spacers are used to increase bearing surface and columnar strength. SPIROL has a complementary Application Engineering Department who can review and recommend a solution to address your specific performance requirements.

For cost effectiveness and quick delivery, our standard materials are best. However, if your application requires something special, our Application Engineers will conduct a comprehensive evaluation and recommend a solution. We will take into account the ability to source the special materials, the ability to cut, form, and the effect on the tolerance of the finished part.

SPIROL offers many variations of our standard products with special features. We can put dimples in the ID that automatically stop wire being inserted half way which allows wire to be placed in the other end and crimped together. We can also provide our products with holes, notches flares and even heads. We can augment standard products with these features, or create a unique special to address the needs of the application.

The Dowel Bushing or Spring Dowel should be installed to at least 60% of its length into the component that will provide primary retention. This will ensure that the exposed end of the Dowel conforms to the hole size of the retaining component.

We can manufacture our products out of a variety of materials - including stainless steel. We offer the most cost competitive solution when our standard off-the-shelf materials are used, however special buys are not uncommon once approved by engineering. When special materials are required, our engineers will review the request to determine feasibility. We will also consider alternative solutions such as high performance coatings or other manufacturing processes that will achieve the desired performance at a lower cost.

Yes, we offer additional lengths other than what is offered as standard as "make to order". However, any special length requires an application review by our Engineering Department to manufacturing feasibility. Most special length Alignment Dowels/Bushings require a minimum order value due to special raw material buys. When length requirements exceed 10 times the diameter, SPIROL Applications Engineers will often recommend the use of a Coiled Spring Pin for alignment rather than a Dowel Bushing or Spring Dowel. With its 2.25 wraps of steel, the Coiled Spring Pin holds itself straighter over the longer length to diameter, and does a great job of aligning components.

We do offer smaller diameter Dowels, however, applications that require diameters less than 5mm or .187", our Coiled Pin may be a better option.

SPIROL focuses on Application Engineering and on offering the lowest installed cost Compression Limiter. We have designed many other types of Limiters for applications that require a unique part. Examples include an application that required a wide open end to slide around a bolt rather than over the bolt, therefore a "U" shaped Limiter was designed. In another application, there was a square tube used as the mounting stud. The application required a snug fit, therefore SPIROL Engineers designed a square version of a Compression Limiter with a thicker wall to accommodate the overall torque and loading requirements.

This is a typical application where tighter a length tolerance is required. SPIROL has a number of solutions that range in cost from special edged material, special secondary end conditioning, to actual precision grinding. SPIROL's Application Engineers will conduct a comprehensive evaluation of your application and recommend the best solution to meet your particular situation.

We have found that when push out retention is most important, dimples offer very low resistance as the dimples are typically smaller and tend to snap off. Grooves and knurls offer more physical area contact with the host and therefore offer superior retention values. SPIROL offers complimentary Application Engineering assistance. We will evaluate your application and recommend the best Compression Limiter to meet your application requirements.

We have seen this happen with the inlet in position as part of the hole. This initial high pressure has caused some flow issues in the past. In these cases, SPIROL has developed a special seam configuration to prevent that from happening. In normal applications, we recommend that the inlet ports for plastic be positioned somewhere other than where the Limiter is positioned and see very little to no issues. The gap specification accounts for the spring back of the material once it is formed.

Coiled Spring Pins have a greater shear strength than most Solid Pins because Coiled Spring Pins are heat treated and the majority of Solid Pins available on the market are not. For more information about this, read this White Paper "Coiled Spring Pins Offer a Unique Balance of Strength and Flexibility."

Depending on part geometry and thickness +/-.0002" (0.005mm)

The thinnest Shims we have produced are 0.0005" (0.0123mm)

SPIROL uses stamping, milling and laser cutting (where authorized) to manufacture our Shims.

Currently, SPIROL only manufactures Shims from different types of metal.

While the terms Disc Springs and Belleville Washers are often used interchangeably, there are several important technical differences that should be clearly understood by Design Engineers. Belleville Washers are primarily used in heavy duty applications fastened together with a bolt where the load is considered static. Disc Springs can be statically loaded either continuously or intermittently, or dynamically subjected to continuous load cycling. Unlike Belleville Washers, Disc Springs are designed specifically to provide a repeatable force-travel relationship, and have a long and predictable fatigue life in dynamic or cycling applications. For a more detailed information, read SPIROL's White Paper "The Difference Between Disc Springs and Belleville Washers."

Deflection of a Disc Spring at a given load is predictable making it possible to calculate force and stress levels in the Disc. As the Disc Spring flexes, stress levels in the Disc change; the greater the change, the faster the Disc Spring fatigues. For detailed information on how to calculate the cycle life of a specific Disc Spring in a particular application, read "How to Calculate the Estimated Fatigue Life of a Disc Spring"

SPIROL offers complimentary Application Engineering. If your application requires a special Disc Spring, our Engineers will evaluate your application and design a unique part to meet your needs. If you would like SPIROL's Engineers to review your application, click here.

Yes, SPIROL offers a line of stainless steel Disc Springs. Please view our stainless steel Disc Spring offering on SPIROL.com.

Coiled Spring Pins can be installed with a hammer, press, air hammer, or automatic pin inserter. The pin size and volume of products being assembled will dictate the best assembly method. Proper fixturing is critical to ensure a successful installation, and it’s also recommended that manufacturers use a spring-loaded alignment pin for assemblies with through-holes. For more information about this, read our White Paper "How to Install a Coiled Spring Pin."

Coiled Spring Pins were designed to be serviceable fasteners. In assemblies with through holes, they can be removed with a punch with the same nominal diameter as the pin. The punch must have a flat, square end. In assemblies with blind holes, Coiled Pins can be removed with pliers or an electrical discharge machine. For more information about this, read our White Paper "How to Remove a Coiled Spring Pin" or watch this short video.

No. Both types of Spring Pins (Coiled Spring Pins and Slotted Spring Pins) have chamfers that are smaller than the hole, and they compress during the installation process to conform to the hole diameter. We only recommend edge breaks on holes where Coiled Pins and Slotted Pins are installed.

Coiled Spring Pins can (and often are) used in plastics. In fact, Light Duty Coiled Spring Pins were specifically designed for use in plastics! Light Duty Coiled Pins exert low forces on plastic holes, extending the functional lifetime of the product. Additionally, the seam is tucked and does not make contact with the hole. That’s why Coiled Spring Pins are the fastener of choice for plastic products with hinges such as plstic door handles, plastic latches and cosmetic cases. For more information about this, read our White Paper "Clever Seam Design Makes Coiled Pin Perfect for Hinges."

SPIROL Standard Slotted Pins were designed with assembly and performance in mind. The most noticeable advantage is that SPIROL Standard Slotted Pins do not interlock like ISO 8752 Slotted Pins. Additionally, SPIROL Standard Slotted Pins have a lower insertion force and superior chamfer design compared to ISO 8752 Slotted Pins. For more information about this, read our White Paper "Advantages of SPIROL Standard Slotted Pins vs. ISO 8752."

SPIROL Standard Slotted Pins are drop-in replacements for ISO 8752 pins. In 99% of applications, no changes are needed to the host components. SPIROL's Applications Engineers will review your application and advise you of any changes required (if any) for your assembly. Contact SPIROL at any one of our Global Locations or fill out this form to provide the information about your specific Pinning Application and one of our Sales Engineers will be in touch with you soon!

Unlike Coiled Pins and Slotted Pins, Solid Pin are permanent fasteners. While more than one type of pin may meet certain requirements, here are some general guidelines when a Solid Pin may be the best option:

• When a head is required for a positive stop or to retain a thin member
  to a thicker member of the assembly
  
• When a smooth, uninterrupted surface is required such as when used
  in conjunction with a pawl or other angular component
  
• When a hollow pin is not suitable such as when the designer is looking
  to plug a hole (i.e. Restrict passage of liquids)
  
• When there is a need to manually align several clearance holes
  
• When increased bending or shear strength is required
  
• When precise hole locations need to be maintained

They are also conducive to automated installation and commonly used to replace screws.

The two common manufacturing methods used to produce Solid Pins are cold heading and machining. SPIROL uses both technologies, but cold heading technology is used to produce our standard product offering. Cold heading is the preferred manufacturing method for the vast majority of applications because it is scrap-less and significantly less expensive than machining at high volumes (> 50,000 pcs). For more information, read this White Paper "The Difference Between Cold Headed and Machined Solid Pins."

Dowel Pins / Straight Pins are commonly used as axles or hinges. Conversely, features like knurls and barbs provide the mechanism to retain the pin in one or more components. Manufacturers should consult with pinning experts at the early stages of their product design to ensure the optimal pin is selected. If you would like SPIROL's Applications Engineers to review your application, contact us at any one of our Global Locations or fill out this form and one of our Pinning Specialists will contactly shortly after we receive your application information.