What are handcuffs made of? Don’t you ever wonder?
What types of materials led to the design of modern handcuffs?
A piece of rope is pretty vulnerable to cutting using some friction and a straight edge.
The practice of restraining someone with a rope has evolved into the development of metal restraints called handcuffs.
Today, standard law enforcement and security industry restraining tools include both chained metal handcuffs and non-metal handcuffs.
Read along because I’ll talk about the materials used for making handcuffs in a bit.
- What Are Handcuffs?
- What Kind of Handcuffs Do Police Use?
- How Do Handcuffs Work?
- How Are Handcuffs Made?
- Can a Human Break Handcuffs?
- What Are Handcuffs Made Of: The Conclusion
What Are Handcuffs?
Handcuffs are restraining contraptions intended for securing a person’s hands by locking the wrists together.
If you are a police officer like me, you probably have plenty of experience with the use of handcuffs.
Variations in restraining devices also include leg cuffs and thumb cuffs, which secure the ankles or thumbs together in place.
What Are Handcuffs Called?
Handcuffs have several nomenclatures, and some nametags are based on the brand and property of the materials used to make them.
General terms that can replace handcuffs include shackles, manacles, fetters, irons, bonds, cuffs, and restraints.
Other terms are less common such as gyves, snips, wristlets, bracelets, and stringers.
Plastic restraints are sometimes called PlastiCuffs, FlexiCuffs, zip-tie cuffs, or zip cuffs.
Some plastic handcuffs are just zip-ties or cable ties.
What Kind of Handcuffs Do Police Use?
The US National Institute of Justice outlines four types of restraints as the standard tools for restraining in both law enforcement and correctional systems.
These classifications are based on each restraining device’s operational requirements, level of security, and reusability.
All of these types are commercially available, and public ownership is allowed almost everywhere.
USNIJ Standard Types of Handcuffs
The USNIJ classifies Criminal Justice System restraints into four types.
Let me talk about each one of them for you to have an idea of how different they in terms of design, locking mechanism, and more.
Type 1 Restraints
Handcuffs from the Type 1 classification may be single or double-looped restraints.
They should have a locking mechanism intended only for single-use, which means they can be disposable and made of plastics.
Type 2 Restraints
Type 2 handcuffs may be single or double-looped restraints that should have an actuating locking mechanism and a standard key.
The presence of a locking mechanism makes this type of handcuffs reusable.
Single-loop Type 2 handcuffs are usually made of plastics, while the double-loop variations can be made of metals or a combination of both metals and plastics.
Type 3 Restraints
The type of more secure handcuffs is the Type 3 restraints, which should be double-looped and have an actuated double-locking mechanism.
The double-locking mechanism also uses a standard key, and the materials used should be very durable.
Type 4 Restraints
Type 4 handcuffs are the most secure of them all.
This type should have a double loop, a unique key, and an actuated double-locking mechanism.
Like Type 3 handcuffs, Type 4 variations should also be made from very durable materials.
How Do Handcuffs Work?
To understand how they work, let me do a rundown of all the essential parts of standard hand restraining devices.
Single-Looped Handcuff Design
As the name suggests, single-loop handcuffs are made of a single loop and a locking mechanism that hold the wrists tight together.
When I use a zip-tie or cable tie as a single-loop handcuff, I wrap it around both wrists put together.
Cable ties or disposable handcuffs have a ratcheting lever strap made of one-way ramps that lock onto the strap head.
They are relatively easy to remove by cutting with a blade or a pair of scissors.
On the other hand, reusable single-loop plastic restraints incorporate the use of a standard handcuff lock and key for loosening or tightening.
Double-Looped Handcuff Design
Plastic double-loop handcuffs comprise two loops, each with a locking mechanism.
The more popular metallic handcuffs also have two loops, each with cheek plates, a pawl, and a ratchet.
The cheek plates hold the locking mechanisms and the pawl. It also holds the attachments that connect the two loops.
Some handcuffs have pivots that allow a 360-degree rotation of the ratchet through the cheek plates.
Depending on the model, double-looped handcuffs may have a single or a double-locking mechanism.
You will find a keyhole on each of the loops for single-lock cuffs and additional lock actuator holes for double-lock cuffs.
Additionally, there are variations in the type of connection between the two loops on metallic cuffs.
You can find these connections as a chain with swivel eyes, a hinge, or a sturdy, rigid material.
Some of these parts can be made of a combination of metals and plastics, but most modern cuffs are usually made of metals or synthetic polymers.
Specifications for Modern Cuffs
Modern metal handcuffs typically weigh about 15 ounces.
The loops have a minimum opening of two inches, while the minimum inside perimeter of the loops is 20 centimeters when the ratchet engages the first notch.
Its maximum inside perimeter should not be more than 16 centimeters when the ratchet engages the final notch.
How do handcuffs work with these specifications?
The obvious answer is anthropometrics. You will want the flexibility of a single restraining device for use with people having varying body sizes.
The minimum opening coupled with both the minimum and maximum outside perimeters allows the restraining of several wrist thicknesses.
This reason is also why I sometimes use lightweight zip-ties as cuffs.
Not only are they easy to use, but they also have better flexibility when it comes to size restrictions.
How Are Handcuffs Made?
Varying types of handcuffs that have different material compositions go through different manufacturing processes.
Nonmetallic handcuffs come from the processing of plastics in factory molds using injection-molded nylon.
The manufacturing process is not so different from the processes involved in making zip-ties or cable ties.
Different molds are used to produce plastic handcuffs in varying thickness, durability, and locking mechanisms.
The manufacture of metal handcuffs begins with the construction of each restraining loop.
Using molten chrome steel, the ratchet, cheek plates, and the pawl are formed in a mold and set aside for cooling.
To assemble the loops, manufacturers construct a spring-loaded pivot bar inside each bracelet.
Each of the bracelets is connected using a chain, a hinge, or a rigid bar.
These connectors are attached using some rivets or through welding.
Is Handcuffs Made of Metal?
As I have already stated several times, handcuffs are not necessarily wholly made of metal.
Although the most secure types of restraints are manufactured from different metals, you can also find quick-use, disposable, and lightweight plastic handcuffs in circulation.
Metal restraints can be made from various metals, including carbon steel, stainless steel, and aluminum.
Alternatively, plastic restraints have come a long way with developments in ultra-durable synthetic polymers that do not easily tear or break.
It is quite common to see handcuffs using a combination of metals and rigid plastics as their base materials.
In addition to this, handcuff keys can also either be plastic or metal.
What Are Handcuffs Made of in Historical Times?
Handcuffs have been used as restraining devices for centuries, not only in law enforcement but also in slavery.
Handcuffs were primarily called shackles, and they were almost always made of metals.
Some restraining devices called stocks and pillories were made of wood and metal, but these types were mostly stationary.
Before the dawn of the industrial revolution, the only way to make shackles is through manual labor in a forge.
These shackles ordinarily came in different sizes because they haven’t invented the ratchet yet.
These one-size-fits-all shackles created a lot of discomfort for wearers with thick wrists and plenty of escape opportunities for people with small wrists.
Can a Human Break Handcuffs?
Escaping from handcuffs is one thing, and breaking a pair of handcuffs is another.
Trying to pry the ratchets from the loops will take a force more extensive than what ordinary humans can give, especially when they are wearing the cuffs.
Some chained handcuffs are vulnerable to twisting along the chain-link connections, but industry standards call for sturdier designs.
A pair of handcuffs have to be old and extensively corroded for a person to break off without so much effort.
How are handcuffs made more durable to avoid such breakage?
The National Criminal Justice Restraint Standards set the bar high by ensuring that handcuffs withstand 495 pounds of tension while pulling the cuffs apart.
To accomplish this, the USNIJ outlines several performance requirements under the NCJRS.
Performance Requirements for Standard Handcuffs
All types of standard US Justice System restraining devices undergo tests and inspections through a series of accredited testing companies.
These requirements stem from the fact that most handcuffs come from private companies, and all the products have to meet several standards and regulations.
The quality inspection for standardized handcuffs ensures that commercially sold restraints do not have any embedded foreign matter.
It also ensures that handcuffs do not have surface peeling, blistering, flaking, powdering, crazing, or cracking.
Workmanship also pertains to having complete, correctly functioning parts. No part should be missing, deformed, misaligned, or loose.
Regulators check that all required markings are correct, legible, and permanently engraved or etched.
Dynamic and Static Load Testing
Dynamic and static load testing checks that both metallic and nonmetallic handcuffs can absorb force, impact, and pressure.
These tests ensure that the handcuffs are not prone to illegal tampering and breakage.
Tests for Nonmetallic Parts
Temperature and solar radiation exposure conditioning apply to handcuffs that have nonmetallic parts.
Applying heat and radiation will test the nonmetallic materials for susceptibility to tearing and breakage.
Some handcuffs have nonmetallic loops that should also undergo a flame exposure resistance test.
This test checks the capacity of the loops to withstand any open flames.
Additionally, the flame exposure resistance test also checks if the material in question is self-extinguishing for avoiding fire hazards.
Tests for Metallic Parts
Handcuffs with metallic parts undergo salt spray exposure conditioning to test for capabilities to resist corrosion.
The keys and parts of Type 3 or Type 4 handcuffs go through decontamination solution exposure conditioning.
This test is another material conditioning technique that checks if the handcuffs are not prone to corrosion from cleaning with bleach.
Plastic and metallic materials should withstand tensile forces such as flexing, rotating, and twisting.
Handcuffs should withstand the tension that occurs whenever the primary loops and connections are subjected to these tensile forces.
Swivel Pry Resistance Testing
If a pair of handcuffs has a swivel, a chain, or a combination of both, a commercially engineered tensile test inspects these components for vulnerability to prying.
Pawl Ratcheting and Double Lock Testing
If a pair of handcuffs has a ratchet arm that rotates 360 degrees around the pivot, the handcuffs go through an operational test that checks this functionality.
Another operational test for Type 3 and Type 4 restraints is the double locking test that verifies the double lock workability.
For additional quality control, the double-locking mechanism also undergoes impact resistance testing.
Cheek Plate Testing
Since handcuff cheek plates hold the locking mechanism, manufacturers also test the cheek plates for durability and strength.
Most metallic components of handcuffs also undergo compression testing.
Both compressive and tensile tests check how the ratchet arms and cheek plates react to bending.
Key Functionality Testing
Corresponding standard and nonstandard keys go through functionality tests that ensure keys work at every unlocking attempt.
Some handcuffs have nonmetallic keys that also undergo tests related to heat exposure.
What Are Handcuffs Made Of: The Conclusion
A pair of handcuffs can be made from different metallic and plastic materials.
If you want the lightweight, disposable types, I suggest you go for plastic handcuffs made of high-grade Nylon 66.
Only the blade of a cutter can cut it into pieces, and you will need a breaking strength of at least a hundred kilograms.
Some parts or even a whole set of handcuffs can be made using synthetic polymers or hard plastics.
Metal handcuffs can be made using carbon steel, stainless steel, nickel-plated alloys, and aluminum.
Much of the designs use chromium-plating and oxide paints to hinder the effects of corrosion.
Alternatively, some handcuffs come in a combination of materials.
Some combine metal parts with synthetic polymer parts, while there are the full-metal models coated with hard plastics.
Interested in learning more about handcuffs? Be sure to check out our article about the different types of handcuffs.