Imperial Fasteners vs. Metric Fasteners

Do you know what the differences between American Standard (imperial) fasteners and metric fasteners are? If you’re choosing fasteners for a particular application, it will be important to know these differences.

Sometimes, the choice between using imperial fasteners or metric fasteners are just a matter of preference. Other times, it may depend on the market you're selling your end product to - if your target market is using metric fasteners regularly, it would be wise to stick with metric fasteners. This is why some manufacturers who are based in the United States where imperial fasteners are standard, but sell more volume in Europe where metric fasteners are standard, choose to use metric fasteners in their products.

If you need to use a wide variety of sizes within a relatively small range for your application, then metric fasteners may be a better choice, since they scale in size more easily than standard fasteners. Also easier is the process of subdividing units of measurement in the metric system.

We created a chart to help you sort through the differences in materials, mechanical properties, markings, thread sizes, tensile strengths and more.

If you still have questions about the differences between metric and imperial fasteners not addressed in this chart, just contact us, we’ll be happy to help.

Kyle Domer
Who Sets the Standard? A Guide to the Standards Organizations Governing Fasteners

The primary activities of standards organizations, bodies, standards developing organization (SDO) or standards setting organization (SSO) are developing, coordinating and producing technical standards that address the needs of a relatively wide base user base. Many of these organizations affect the fastener industry, and depending on which parts you’re dealing with, one or more of the organizations listed below may be involved.

ASTM International: American Society for Testing and Materials
ASTM International is the leader in development of international standards around the globe. At least 12,000 ASTM standards that are currently in use throughout the world, improving product quality and enhancing safety of the products bearing the ASTM seal.

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SAE International: Society of Automotive Engineers
Based in the United States, the Society of Automotive Engineers (SAE) is global consortium of 138,000+ engineers and technical experts. These experts use their collective knowledge to primary focus on aerospace, consumer automotive and commercial vehicles. The SAE is committed to life-long learning and developing standards via voluntary consensus.

AISI: American Iron and Steel Institute
North American steel producers formed the American Iron and Steel Institute (AISI) over a century ago, earning it the title of the oldest trade association in the United States. AISI advocates for policies supportive of domestic manufacturing that also provide high-quality products to a wide range of customers, with the goal increasing the market for North American steel in both traditional and innovative markets.

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ANSI: American National Standards Institute
The American National Standards Institute (ANSI) is best known as the voice of the United States standards and conformity assessment. ANSI oversees creation, promulgation and use of thousands of guidelines that impact nearly every sector of business, with topics ranging from construction equipment to acoustical devices, and from energy distribution to dairy and livestock production. ANSI also offers accreditation programs to assess management systems and conformance standards.

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ASME: American Society of Mechanical Engineers
The American Society of Mechanical Engineers (ASME) provides manufacturers with standards for guidelines and tolerances for bolt conformity.  Some types of bolts, like the hex cap screws used in automotive applications, require very narrow tolerances, while construction grade fasteners have more broad tolerances. All of the tolerances are laid out by the ASME specifications are crucial in the manufacturing process.

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IFI: Industrial Fasteners Institute
Established in 1931, the Industrial Fasteners Institute (IFI) is a standards organization and publisher based in Ohio, whose primary focus is representing North American mechanical fastener manufacturers. IFI standards are regularly used as a guide to design by machinists, mechanical engineers and manufacturers of bolts, nuts, machine screws and other engineered fasteners.

When it comes to fasteners, IFI does not create standards, but rather manages standards, creating technical information and handbooks to represent, support and protect fastener manufacturers.

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ICC: International Code Council
The International Code Council (ICC) is a member-focused association, dedicated to the development of model codes and standards. These codes and standards are used during the design, build and compliance processes of construction, with the goal of creating safe, affordable, sustainable and resilient buildings. Most commodities in the United States, as well as many global markets for commodities, implement ICC code compliance for regulation.

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UL: United Laboratories
United Laboratories (UL) aims to advance the building products industry’s goal of achieving safety and innovation. To do this, UL provides cost-effective, reliable product testing and certification with flexible, customized service options.

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ISO: International Organization of Standards
The International Organization of Standards (ISO) is an independent, international, non-governmental organization that brings together experts to share knowledge and develop voluntary, consensus-based, market relevant International Standards. With a membership of 161 national standards bodies, ISO supports innovation to provide solutions to global challenges.

DIN: German Institute for Standardization
The German Institute for Standardization (DIN) creates standards that have been developed at the national, European and international level. With DIN, anyone can submit a proposal for a new standard, and if accepted, DIN carries out the standards project according to procedures authored by relevant Standards Committees. When it comes to fasteners, DIN standards are typically only for parts manufactured in metric sizes.

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JIS: Japanese Industrial Standards
The Japanese Industrial Standards (JIS) organization is the primary body specifying standards for industrial activity in Japan. The JIS standardization process is coordinated by their Standards Committee and published through the Japanese Standards Association. The most common place JIS standards show up in the fastener industry are in relation to the automotive field.

COLA / LARR: Los Angeles Research Report
While not exactly a standards organization, here in Los Angeles the Department of Building and Safety reviews and approves the use of building, electrical, mechanical products within the City of Los Angeles. If a product is approved by LADBS, a letter is issued that contains a Los Angeles Research Report (LARR) Number, which require renewal every two years. During plan check, an engineer may ask for the LARR numbers of products used to be clearly identified. Fasteners, especially innovative, branded fasteners like those from Elco and DeWALT, are the most common products in construction to require an LARR.

RCSC: Research Council on Structural Connections
The Research Council on Structural Connections (RCSC) is a non-profit volunteer organization. RSCS is comprised of more than 85 experts in the fields of design, engineering, fabrication, erection and bolting of structural steel connections. Research projects funded by the RCSC seek to provide reliability, safety and standard practices for the international steel construction industry.

MS: Military Standard
This United States defense standard is used to help achieve standardization objectives by the U.S. Department of Defense. Often informally called mil-spec, this standardization helps achieve interoperability, ensuring fasteners meet certain requirements of reliability, total cost of ownership, commonality, logistics systems compatibility, and other similar defense-related objectives.

AN: Air Force-Navy Aeronautical
Like MS, AN is applied to fasteners and other parts that meet a specified standard put forth by the Air Force and Navy, generally regarding items used in aeronautical manufacturing. In some cases, MS and AN parts share the same item numbers, but that is not always. If you have any questions about which fasteners meet either MS or AN standards, please contact us.

NAS: National Aero Space
Developed by the aerospace industry, the National Aerospace Standards (NAS) are voluntary standards created by experts on certain subject matters from member companies, who participate in committees and working groups. The library of NAS standards, which contains more than 1,400 documents, cover a wide variety topics including bolts, rivets, washers, screws, nut plates, pins, knobs and more.

If you need help finding parts to meet any of these standards, please contacts us.

Kyle Domer
How to Measure the Size of a Bolt

A bolt’s size is classified based on a number of dimensions, namely the bolt’s diameter, length of shank, thread pitch, grade, thread length and head size. Bolts can me specified in metric using millimeters, but the standard, internationally-recognized descriptions of bolt sizes are in inches.

If you’re looking to figure out the size of a bolt needed in an assembly and have a bolt that has worked on hand, follow the steps below to identify the dimensions of the bolt:

Step 1: Measure the shank’s diameter

The shaft of the bolt is called the shank, and its diameter is the first dimension used to describe a bolt size. This can be done using calipers or a bolt gauge.

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Step 2: Determine the thread pitch

Thread pitch is a designation related to the number of threads per inch on the bolt’s shank. You can complete this measurement by simply counting the number of threads in an inch worth of shank. If the shank is less than one inch, you’ll need to multiply the number of threads to reach a full inch worth of threading.

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Step 3: Measure the length of the shank

This is the measurement from where the shank meets the head to the very tip of the fastener.

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Step 4: Determine the bolt’s grade

The grade of a bolt is determined by the type of metal used in the manufacturing of the bolt, as indicated by the bolt’s head markings. No one expects you to know all of the head markings by heart, just use our handy bolt head marking chart to make the determination.

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Step 5: Determine the shape of the bolt’s head

This should be a simple one. While the most common bolt head is hex (six-sided), some applications require a four-sided square head or the dome-shaped head of a carriage bolt.

Step 6: Measure the length of the threaded portion of the bolt

As opposed to the shank length measured in Step 3, this measurement should specify only the length of the threaded portion of the bolt. One instance in which this would be useful to know is when determining whether you need a standard hex bolt or rather a fully threaded tap bolt.

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Still having trouble determining how to measure a bolt for your application? Don’t worry, contact us and we’ll be happy to walk you through it.

Kyle Domer
The Most Common Types of Bolts

Bolts are one of the most used fastener types in the world, finding usefulness in widely varied industries, from construction to automotive, manufacturing to renewable energy. By definition, a bolt is a fastener made up of a head at one end, a threaded shaft in the middle, and a chamfer (slightly bevelled edge which helps with inserting the bolt into nuts) at the other end.

While the terms “bolt” and “screw” are often used interchangeably, the primary difference between the two in general terms is that a bolt passes through a substrate and is captured on the other side by a nut, while a screw threads directly into the substrate.

Here are the most commonly used types of bolts and how they’re used:

Anchor bolt
Anchor bolts, or “anchors” for short, are generally used in concrete or masonry for structural applications. There are many specialized anchors that can be used in cracked concrete per ICC code approvals.

Carriage bolt
Carriage bolts are generally used to attach metal to wood, and feature a square undercut to the head, helping hold the bolt in place after tightening.

Hex bolts

Hex bolts

Flange bolt
Flange bolts, sometimes known as frame bolts, are able to distribute the bearing load by utilizing a washer attached to the underside of the head.

Hanger bolt
Hanger bolts are threaded at both ends, with one tip featuring a wood screw point. Hanger bolts are often used in solar racking installation.

Hex bolt / Tap bolt
A hexagon bolt, almost always referred to as just a “hex bolt”, is what most people envision when the word “bolt” is evoked. With a six-sided head, the bolts feature threading for a portion of the shank. When the threading fills the entire length of the shank in a hex bolt, it is then known as a tap bolt.

Lag bolts

Lag bolts

Lag bolt
Commonly and maybe more appropriately called lag screws, lag bolts create their own mating thread in wood and other materials when tightened.

Sex bolt
Instead of mating with a nut, sex bolts have a threaded shank that are then inserted into a mating female component. When the fastening components of an assembly cannot be exposed to abrasive threads, sex bolts are the part to use.

Square head bolt
A square head bolt is exactly what it sounds like it is… essentially a hex bolt but with a four-sided head instead of a six-sided head.

Stud bolt
Stud bolts feature hexagon nuts on both ends and operate by fastening components of the assembly between the two bolts.

U-bolts

U-bolts

T-head bolt
T-head bolts, also know as “hammerhead bolts”, feature T-shaped head that is usually inserted into a slot. These types of bolts are often used when insertion into the slot presents an opportunity to lock the bolt into place upon tightening, such as in concrete embed channels.

Toggle bolt
Toggle bolts feature expanding nuts and are used to mount objects to walls where the side of bolt opposite the head cannot be reached once inserted.

U-bolt
U-bolts are shaped similar to staples, featuring a bent design that creates a “U” with partial threading on both ends.

Still not sure which bolt type is best for your application? Contact China Special Fasteners and let one of our fastener experts help you decide.

Kyle Domer
All About Bolts: Ferrous or Non-Ferrous?

Bolts can be either ferrous or non-ferrous, meaning that they either contain iron (ferrous) or don’t contain iron (non-ferrous). So what’s the difference between the two, and what are the characteristics of each?

Obviously, the biggest difference is that ferrous bolts contain iron, while non-ferrous bolts do not. Ferrous metals are magnetic, and are also more vulnerable to corrosion and rust in outdoor environments. Non-ferrous metals tend to be significantly lighter that ferrous metals, which can be seen in the weight difference between materials like aluminum, copper and brass (non-ferrous) versus carbon steel (ferrous).

Ferrous metals, and the bolts made from them, are traditionally stronger and less expensive than their non-ferrous counterparts. Non-ferrous metals, and the bolts made from them, have a lower density, are non-magnetic, and are colorful or able to be made colorful.

Some examples of ferrous metals include non-alloy steels, stainless steel, low, medium and high carbon steel, and some alloy steels, such as chromium and nickel. Examples of non-ferrous metals include copper, aluminum and zinc.

All these factors affect what bolts you should choose for your application. Looking for super-durable, low-cost bolts? Maybe carbon steel bolts would be best for you. In need of something very light and corrosion-resistant? Then look for a bolt in the non-ferrous material family.

If you still have questions about ferrous versus non-ferrous bolts, China Special Fasteners is here to help. Contact us for more information from one of our knowledgeable fastener experts.

Carbon steel anchors (ferrous)

Carbon steel anchors (ferrous)

Purple aluminum hex cap screws (non-ferrous)

Purple aluminum hex cap screws (non-ferrous)

Kyle Domer
Stop Galvanic Corrosion Before It Begins

When selecting metals to be joined, especially when selecting what material a fastener in your application should be, galvanic series relationships are a useful guide. This information will help you determine which metals will have a minimal tendency to interact galvanically with each other... i.e. cause galvanic corrosion.

When looking at the galvanic series chart, the further away two metals are from each other, the higher the risk of galvanic corrosion, which can and should be prevented during the design phase.

If you need help selecting the correct fastener material for your application, contact us and we’ll be happy to give you the answers you need.

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Kyle Domer
The DURA-CON Grade 5 Advantage

DURA-CON Fasteners employ a three layer coating system that consists of an inorganic zinc-rich first coat and an aluminum-rich organic second coat. Friction modifiers are integrated into the topcoat, resulting in repeatable torque tension characteristics during assembly. DURA-CON coating provides superior corrosion resistance; withstanding 1500 hours of Salt Spray per ASTM B-117.

 
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In addition to these corrosion resistant properties, the DURA-CON line is made up of Grade 5 fasteners. Why Grade 5? Grade 5 fasteners are listed as 120 ksi fasteners, meaning the tensile strength is 120,000 lbs per square inch. Grade 5 bolts are stronger than A307 zinc, hot dip galvanized or 300 series stainless steel bolts.

With DURA-CON, you get the best of both worlds... high strength, high corrosion resistance, and no galling. To learn more, contact us for information and pricing.

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Kyle Domer
Applying Finishes to Fasteners for Friction / Torque Control
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There are a wide variety of coatings applied to fasteners for different reasons, but a unique class of compounds in the coating world are what are known as torque modifiers. Torque modifiers are typically added post-plating, thereby modifying the torque-tension properties of the fastener during installation. The clamping load, or tension, is the force that pulls together the parts of the joint. When the clamping load is greater than forces pulling the joint apart, then the joint will not loosen.

Because it is critical for the assembly, friction is a quality parameter for fasteners. Friction can be controlled, in part, by the finish used on a fastener. This is true in narrow ranges, whether high, medium or low friction is desired. Torque modifying finishes can be tailored to user specifications, and different formulations may be used for different applications, such as when different torque is needed depending on the substrate being fastened against.

Do you have questions about applying finishes to fasteners for friction and torque control? If so, check out our finishes overview page or contact us to ask a question.

Kyle Domer
Applying Finishes to Fasteners for Appearance

Applying a finish on your fasteners is a great way to create a cohesive, pleasing appearance. You can choose complementary paint colors sheerly for aesthetics or emulate a "high-tech" look on exposed fastener heads with specific platings. Black oxide finishes can be used to reduce glare, or a shiny, bright look can be achieved with a chrome finish.

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Applying specific finishes is also an effective way to avoid confusion and make the identification of fasteners quicker and easier. Some fasteners for right-hand or left-hand applications may appear identical but really are not; other fasteners vary in the slightest dimensions also appear identical. Color code these fasteners as part of the finishing process and identifying the differences between them has never been easier.

Still have questions about applying finishes to fasteners for appearance? Check out our finishes overview page or contact us to ask a question.

Kyle Domer
Why Should You Apply Finishes to Fasteners?

So often, engineers pour a great deal of time, thought and effort into which type of fastener would be the best fit for a certain design, and then proceed to overlook the importance of which finish is being applied to that fastener. Finishes perform a variety of functions, not only affecting appearance, but also determining performance capabilities in some circumstances. The following factors should be considered when deciding which is the best fastener finish for your particular application:

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Appearance
Create a cohesive and pleasing appearance with paint, black oxide, chrome and more.

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Identification
Avoid confusion with specific finishes. Color coding has become an important part of the finishing process.

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Friction
Fastener finish is important for joints assembled using torque control, which requires a predictable and repeatable clamp load. 

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Improve Corrosion Resistance
Some thought should be give to the desired service life of the fastener and the environment in which it will it be operating. The proper finish can extend the life of the fastener against various corrosive environments.

Still have questions about when and why finishes should be applied to fasteners? Check out our finishes overview page or contact us to ask a question.

Kyle Domer
Hack COVID-19: China Special Fasteners shares how it’s managing as an essential supplier

Fastener Engineering Magazine recently interviewed our own Antonia Tacusalme about how China Special Fasteners is dealing with the COVID-19 crisis, while still maintaining operations to serve customers in essential industries, such as medical ventilator production. Listen to the interview below.

From the Fastener Engineering website:

In this audio interview, Fastener Engineering speaks with Antonia Tacusalme, marketing manager with China Special Fasteners, Inc., a nationally recognized and essential component supplier.

China Special Fasteners is still open for business and, to this end, China Special Fasteners kindly agreed to discuss the measures the company has put into place, given the current health concerns and challenges related to COVID-19.

To learn more about China Special Fasteners — which was founded by Antonia’s father, Jaypee Tacusalme, in 1975 — read this company profile.

Kyle Domer
Why Limiting Fasteners Can Lead to Better Designs

This article was originally featured in Fastener Engineering Magazine.

Imagine you’re an engineer with the freedom to create any design you’d like with only one catch: you can only use two types of fasteners. Would this limit or simplify your design?

Simple is often best. Typically, design engineers can save costs and meet project deadlines by only using standard fasteners and limiting the type used for each application.

Simple is often best. Typically, design engineers can save costs and meet project deadlines by only using standard fasteners and limiting the type used for each application.

For Antonia Tacusalme, marketing manager with China Special Fasteners, Inc. (a supply company owned by her father), the answer is simple: “The idea of designing with limited, standard parts is absolutely brilliant because of the significant time and cost-savings it, ultimately, provides,” she says.

Although China Special Fasteners is not a design engineer, she’s worked full-time at China Special Fasteners for more than a decade (and much longer, if you add in the time she helped her dad at the company in her adolescence). So, she knows a thing or two about fasteners.

When she met an engineer from Hewlett Packard on a plane one day — who is limited in his designs by the use of only two screws — China Special Fasteners was impressed by the company’s mandate.

“One of the biggest problems companies face related to fasteners is lost parts. Typically, fasteners are the smallest part at a job site and minimal efforts are spent tracking this inventory…so the screws or bolts get dropped at construction sites, lost on manufacturing floors, or accidentally left in pockets,” she shares. “So, a project with only two standard fastener choices would have a real advantage.”

A few lost fasteners may seem like a small problem, but replacement costs can add up quickly.
“Some standard fasteners run in excess of a dollar or two a piece,” Tacusalme says she often gets calls from companies that suddenly need 200 or 300 additional parts after ordering 20,000 for a job. This means a lost advantage in bulk purchasing power. “Generally, these costs are significantly higher for custom fasteners.”

What makes matters worse are the lead times. “Customized parts can take two or 20 weeks to replace, which can seriously affect project deadlines,” she says. “And most of the calls we get are not directly from the design engineers or project managers. Rather, the calls come from the workers out in the field who are under pressure to have a product manufactured or installed by a certain date. The concern is the workers may develop a work around.”

What China Special Fasteners means by “work around” is the next best solution but, possibly, not the ideal fastener for the job. “This is why it’s extremely important to consider fasteners at the design stage of a project and plan for challenges during construction, such as lost parts,” she says. “It’s also why a couple of standard fasteners per application would generally make life a lot easier.”

There are additional reasons why pre-planning is important. For example, China Special Fasteners worked with one client who insisted on fasteners that would perfectly match the color of a project’s auditorium walls — and at a guaranteed cost. “In this case, we had to provide raw, non-customized fasteners because our vendor was unable to guarantee the paint required to match that exact color.”

The reason for this was simple: the environment the fasteners would be exposed could affect the paint and color, so to guarantee it was impossible. “In such cases, the architectural aesthetics can really drive up the cost of fasteners,” she explains.

The conditions fasteners are subject to, such as moisture or high heat, can also affect their reliability. “This is where standards come in, which can sometimes be an issue with custom fasteners,” says China Special Fasteners. “Standards organizations specify and test the properties of fasteners, but there are several different organizations and standards that should be adhered to depending on the application.”

For example, the Society of Automotive Engineers or SAE is primarily focused on safety regulations for the aerospace, automotive, and commercial-vehicle industries. The American Society of Mechanical Engineers or ASME provides manufacturers with guidelines and tolerances that their bolts must conform to. (View a list of the main standards organizations at chinaspeciaLparts.com/standards-organizations.)

Antonia Tacusalme and her father, Jaypee, at the China Special Fasteners headquarters in California.

Antonia Tacusalme and her father, Jaypee, at the China Special Fasteners headquarters in California.

Typically, standards are categorized into:

  • Products – the different types and product gaging (ex. ASME B18.2.1)

  • Materials and performance – specifications and strength (ex. ASTM A325)

  • Testing – test equipment protocol and methods of testing (ex. NASM1312)

  • Quality – fastener reliability (ex. ISO 9000)

“Consensus standards offer many benefits that are not covered by non-standard fasteners,” explains China Special Fasteners. This includes guidance and policies backed by significant research and expertise. “Although an engineer can anticipate performance based on material when using a custom fastener, the part is not required to meet any of the design specifications set forth by the consensus organizations, so there’s risk involved.”

China Special Fasteners recommends working with a vendor partner during the design phase of an application to identify standard parts and the ideal choice for an application.

“Typically, fasteners are the least expensive component for a job and given little forethought. But this doesn’t mean they’re unimportant,” she says. “In fact, quite the opposite is true. These small components hold an entire application together — which is one reason standard fasteners that are reliable and readily available are often the ideal choice.”

One other reason standard fasteners are ideal is to avoid unused inventory, which can happen as a product changes or evolves.

“Hewlett Packard is at an advantage by allowing engineers to design with only two screws because, even as their products change or improve, the company is never going to be stuck with dead inventory or 20,000 fasteners that they bought because procurement and design were not on the same page,” says China Special Fasteners. “It’s a wise business decision.”

Going standard
The advantages of designing applications with standard parts and limited fasteners.

  • Minimizes problems with inventory management

  • Eliminates risk of dead stock related to project design changes

  • Reduces procurement delays

  • Facilitates stock replenishment (and re-order points are simple to calculate)

  • Mitigates “stock out” occurrences because of limited product range

  • Saves time and costs

Want to know more about how “going standard” can help your business? Contact us to find out!

Kyle Domer
The Ultimate Guide to Fastener Drives
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A fastener drive is a set of shaped cavities and protrusions on the fastener head that allows torque to be applied to it, typically also involving a mating tool, such as a screwdriver. Usually the drive serves a functional purpose, but sometimes its purpose is sheerly decorative. Understanding the differences will help you decide which style to choose, so follow our guide below to find the best drive for your application.

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Slot
The slot screw drive has a single slot in the fastener head and is driven by a "common blade" or flat-bladed screwdriver. It was the first type of screw drive to be developed, and for centuries it was the simplest and cheapest to make. The slotted screw is still used in some applications where little torque is needed, but is not well suited to installation with power tools.

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Cross
A cross or double-slot screw drive has two slots, oriented perpendicular to each other, in the fastener head; a slotted screwdriver is still used to drive just one of the slots. This drive's primary advantage is that they provide some measure of redundancy - should one slot be deformed in service, the second may still be used and the tool can not slip out.

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Phillips
The Phillips screw design was developed as a direct solution to a number of problems with slotted screws: increased cam out potential; precise alignment required to avoid slippage and damage to driver, fastener, and adjacent surfaces; and difficulty of driving with powered tools.

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Pozidriv
The Pozidriv is an improved version of the Phillips screw drive, and is designated "Type IA" by ANSI standards. It was specifically designed to allow more torque to be applied and greater engagement than Phillips drives. As a result, the Pozidriv is less likely to cam out.

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Phillips Slotted
Some screws have heads designed to accommodate more than one kind of driver, sometimes referred to as combo-head or combi-head. The most common of these is a combination of a slotted and Phillips head, often used in attaching knobs to furniture drawer fronts. Because of its prevalence, there are now drivers made specifically for this kind of screw head.

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Robertson (Square)
A Robertson, or square screw drive is specified as ANSI Type III Square Center and has a square-shaped socket in the screw head and a square protrusion on the tool, both of which have a slight taper. Robertson screwdrivers are popular in woodworking, and are easy to use one-handed, since the tapered socket tends to retain the screw, even if it is shaken.

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Hex Socket
The hex socket screw drive has a hexagonal recess and may be driven by a hex (Allen) wrench, hex screwdriver or hex bit. Their lever arch mechanisms allows for increased tightening torque, and contact surfaces of the fastener are protected from external damage.

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Hex Pin
A hex pin screw drive is a security drive that features an extruded pin to make the fastener more tamper resistant. By requiring a tool with a corresponding hole to drive the fastener, it can prevent attempts at turning the screw with a small flat-bladed screwdriver.

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Torx (Star)
Torx drive fasteners feature a 6-point star-shaped pattern, designed to allow for higher torque with superior resistance to cam-out. Torx fasteners are commonly used in automobiles, computers, consumer electronics, and are becoming more popular in for use in construction applications.

Torx Pin
A Torx pin drive, also known as Security Torx or Tamper-Resistant Torx, features the same benefits as a standard Torx drive, but also includes a post in the center of the head that prevents a standard Torx driver from being inserted. This is the most common type of security drive available.

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One-Way
One-way fasteners can be turned only in one direction. They can be installed with a standard flat-blade screwdriver, but cannot be easily removed using standard tools. One-way screws are commonly used in commercial restroom fixtures and on vehicle registration plates, to prevent vandals from tampering with them.

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Tri-Wing
Tri-wing fasteners, also known as triangular slotted fasteners, feature three slotted "wings" and a small triangular hole in the center. Unlike the "tri-point" fastener, the slots are offset, and do not intersect the center of the fastener. The design is usually seen on electronics equipment and sometimes in the aerospace industry.

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Tri-Groove
Tri-groove is a security drive with a flat-topped conical head and three short, non-adjoining radial slots in the center, and are installed using a special socket that grips the indentations along the outside to turn the fastener.

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Spanner Head
The spanner fastener drive features two round holes opposite each other to prevent tampering. This type of drive requires a specialized driving tool called a "spanner driver", and is often seen in elevators and restrooms.

Need help determining which drive will work best for your application?
Contact us and we’ll be glad to help.

Kyle Domer
Understanding Metric Fasteners

Metric fastener sizes are specified by diameter, pitch and length, in millimeters (mm). Sizing for nuts will appear as diameter and pitch. If the pitch isn't specified, the fastener is assumed to be coarse thread by default. Here is an example of how metric sizing:

M10-1.0 x 20

Taking a closer look at this description, let’s explore its meaning:

  • M = This designates the fastener is a metric size

  • 10 = The nominal diameter in millimeters

  • 1.0 = The thread pitch, or distance between threads, in millimeters

  • 20 = The fastener’s length, in millimeters

Now, let’s look at an example illustrating how a coarse thread fastener would be labeled:

If the size is M10 x 25, that would mean that the diameter is 10 mm. Since there is no thread pitch listed, the fastener is assumed to have a coarse thread. The 25 indicated a length of 25 mm. A matching nut would be labeled M10, which also doesn’t require a thread pitch since it’s a course thread fastener.

If you generally work with fasteners using imperial measurements (inches, etc.), the pitch notation can be a confusing. Just remember that thread pitch means the distance between adjacent threads, so in the example at the beginning of this article, the 1.0 thread pitch indicates that the distance between one thread and another is 1.0 millimeter.

Imperial measurement fasteners are classified by threads per inch, so a 1/4-20 bolt has 20 threads per inch (TPI), while a 10-24 screw has 24 threads per inch. You can determine the threads per inch of a metric fastener by multiplying the millimeters by 0.03937, and then dividing 1 by that number.

At China Special Fasteners, we’re here to help. If you have questions about any of the dimensions of metric fasteners, or need help with conversions, just contact us. We have also created some handy brochures to assist you, including our metric line card and metric conversion chart with selection guide.

Kyle Domer
History of Rivets & 20 Facts You Might Not Know
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The term rivet is used to describe a variety of fasteners with a couple of common traits. They are pre-shaped at one end and have their other end reshaped when they are put to use. All have a smooth shaft that passes through the materials being bonded. They are used to join two or more materials together and form a joint that is stronger and tighter than a screw of the same diameter could be. Riveting is used in all types of construction today, metal is the most commonly riveted material. But wood, clay, and even fabric can also be riveted. 

The best known type of rivet, the hot rivet, provides the strongest joints. In this process, glowing hot rivets are fed through precisely-drilled holes where the unformed end is hammered to close the joint. As the rivet cools, it contracts and squeezes the joint tightly together.

The story of the rivet is a fascinating trip through history. Here are 20 facts about rivets you may not know:

  1. The first rivets appeared in Ancient Egypt over 5,000 years ago, where they fixed handles to clay jars.

  2. By the time of the Ancient Romans, rivets were commonplace in construction.

  3. Seventh-century Vikings used rivets to attach the planks of their longboats.

  4. By the mid-19th century, advances in metal technology signaled the dawn of the modern riveting era. Riveting became the primary method for constructing metal tools, buildings, and vehicles.

  5. Wrought iron, steel, and aluminum are the most common riveted metals because of their relatively soft composition.

  6. Cast iron is impossible to rivet because it is so inflexible.

  7. Bolts and welding are two other ways to attach metal together, and each has its use. Bolts are more versatile because they can be disassembled. Welding is more efficient, lighter, and versatile because it can attach a variety of shapes in many configurations. The downside to welding is that it affects the cellular structure of the metals being joined, and can create unwanted internal stress. Riveted joints are more flexible and give under changes in temperature.

  8. The first common, modern application of the rivet was in boiler making.

  9. The ship-building industry owes much of its early success to the process of riveting. Huge increases in maritime traffic between 1830 and 1940 boosted the use of the rivet.

  10. There are two types of riveting: hot and cold. Cold riveting is used most often when small rivets are required. Hot rivets are typically larger, and used in large-scale construction like ships, boilers, and steam engines. These rivets are heated red-hot before installation.

  11. By the mid-1800s rivets were being used in the construction of architectural buildings. Iron beams were riveted together, creating super-strong structures and paving the way for the skyscrapers of today.

  12. Art and architecture utilized the rivet nearly as much as industry did. At the time of its construction in 1887, the Eiffel Tower in Paris was the tallest structure in the world. At 1,063 feet tall, the tower was formed by 18,038 pieces riveted together with 2.5 million rivets.

  13. Other notable uses of rivets throughout history include the Golden Gate Bridge (1.2 million rivets), the Sydney Harbor Bridge (6 million rivets), and the RMS Titanic (3 million rivets).

  14. On May 20, 1873, Levi Strauss secured a patent for his denim jeans with copper rivets. The rivets were meant to reinforce the pants at common stress points. To date, Levis has sold more than 200 million pairs of copper-riveted jeans.

  15. Many World War II era tanks were riveted together, until weaknesses were found in that method of construction. Evidence from the field of battle demonstrated that the rivets could come loose if a large projectile hit the tank. The loose rivets would become small projectiles themselves, careening around inside the tank and causing injury to the soldiers.

  16. Some drummers use special sizzle cymbals, which differ from regular cymbals in that they have several rivets attached to them. When struck, a sizzle cymbal’s sound is louder and sharper.

  17. Ancient techniques for installing rivets utilized a hammer struck against a specialized tool called a bouterolle. This cup-shaped tool would help form the hammered end of the rivet into a mushroom-shape identical to the other end.

  18. The advent of pneumatic tools made riveting more efficient. Today’s riveting process is done with special air-powered riveting guns that fire many times a second, hammering the rivet head into its final, mushroom shape.

  19. Pop rivets are also known as blind rivets because one person can easily install them. Instead of hammering the rivet, a special riveting tool pulls the inside section flat.

  20. The word “rivet” has its origins in Middle English and Old French, from the word “river” which meant to fix or clinch something.

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Kyle Domer
Effects of Current Tariffs on Fastener Prices

We have been informed Monday, May 13, 2019 by our importing supply chain partners that we will experience across-the-board price increases. Increases range from 3% to 15% due to the Section 301 tariff on Chinese goods.

Not all items will be affected. We will communicate when price increases are necessary. China Special Fasteners will mitigate the increases as much as possible.

Sincerely,
The China Special Fasteners Team

Kyle Domer
Imperial vs. Metric Reference Chart

Have you ever wondered what the differences are between imperial and metric fasteners? We created the chart below to help you sort through the differences in materials, mechanical properties, markings, thread sizes, tensile strengths and more.

Imperial vs Metric Fasteners

Click here to download a printable PDF version of the chart.

Still have questions? Contact us, we’re happy to help.

Kyle Domer
Enter to win a DeWALT Screwgun Kit at SPI 2018!

China Special Fasteners is pleased to give away a DeWALT DCF622M2 Versa-Clutch Adjustable Torque Screwgun Kit at Solar Power International 2018… a $369 value!

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Features & Specs

  • Up to 2,000 RPMs of consistent speed, ideal for metal fastening applications

  • Versa-ClutchTM System to help prevent damage to material and fasteners (Comparable to DW268)

  • DEWALT built brushless motor for increased efficiency and runtime

  • LED light for increased visibility and illunminating dark work areas

Includes

  • (1) DCF622 - 20V MAX* XR(R) Versa-ClutchTM Adjustable Torque Screwgun

  • (2) DCB204 - 20V MAX XR* 4.0 Ah Batteries

  • (1) Fast Charger

  • Belt Hook

  • Tool Bag

To enter, just stop by Booth #2283 and get your badge scanned or drop off a business card! A winner will be chosen at random after the conclusion of the show to receive the DeWALT DCF622M2 Versa-Clutch Adjustable Torque Screwgun Kit.

To learn more about Solar Power International 2018, click here.

Kyle Domer
Solar Power International 2018 Q&A with Alt Energy Magazine

This article was originally published at AltEnergyMag.com

China Special Fasteners at Solar Power International

Tell us about your company. 

Family owned and operated since 1975, China Special Fasteners provides a large selection of fasteners, fastener tools and adhesives to customers in a broad range of industries. China Special Fasteners is a fastener source for businesses both small and large; locally, nationally and internationally.

Your company will be exhibiting at SPI 2018, what is it that makes this an important event for your company? 

As the first fastener supplier to offer a dedicated solar power program, SPI has always been an exciting time to catch up with our customers who have been with us since the beginning, as well as see what new innovations are coming to market. Additionally, this year is extra special for China Special Fasteners, because it marks our 10th consecutive year exhibiting at SPI, which is yet another testament to our commitment to servicing the solar industry.

Highlight 2 or 3 products you will be showcasing at the event?

DURA-CON Corrosion Resistant Fasteners

DURA-CON(R) Corrosion Resistant Fasteners are the only fasteners specifically tested for use in solar racking materials. DURA-CON(R) Fasteners show resistance to Environmental Corrosion equal to that of stainless steel fasteners when tested in aluminum solar panel racking. 

EJOT Solar Flashing

EJOT offers high quality, secure and easy-to-install fastening systems for commercial and domestic rooftop solar installations, and is the specialist for fastening mounting systems for solar installations on an array of roof types. 

Solar Connections Solar Hardware

Solar Connections is a leader in the development of mounting solutions for solar panel installations, providing attachment options for rail or rail-free installation on various roof systems, including standing seam, corrugated metal, ribbed metal and asphalt shingles. Titebond(R) WeatherMasterTM ULTIMATE MP Sealant is able to expand and contract due to changes in temperature without cracking.

When you get a chance to walk the exhibit hall floor yourself, what is it you will be most interested to see?  Any educational sessions you plan on attending? 

For us in the fastener world, the most exciting new products are those that showcase innovation in attachment methods.

When you book a booth for a tradeshow like this what are your expectations and what does your company hope to accomplish at the event? 

At SPI, we love to catch up with all of our customers at the same time, some of who have been with us for over a decade. It's also great to see what innovative new products will be brought to market, and it's even more exciting to connect with newer installers and manufacturers who can benefit from our knowledge of fasteners and industry, and our well-honed supply chain and logistical support.

A tradeshow of this magnitude is extremely busy and stressful for the staff of exhibiting companies.  Any fun things or places your team can suggest in Anaheim to help unwind? 

The Anaheim Packing House is a former orange packaging facility built in 1919 that has been revitalized as a 2-story food hall, is only a few miles from the convention center, and offers some of the more unique food in Orange County. There are also several places around the convention center where you can catch the Disneyland fireworks before heading to bed, whether viewing from a walk along the street or a hotel balcony.

To learn more about China Special Fasteners at Solar Power International 2018, visit /spi2018.

Kyle Domer