How to Choose the Right Coils for Your Project
Plastic coils, also known as spiral coils or coil bindings, are recognized for their versatility, flexibility, and clean appearance.
BINDAPLY™ coils are made from a flexible polyvinyl chloride (PVC) material and formed into a continuous, spring-like coil. The coil is inserted through punched holes along the edge of the pages and then spun into place and crimped on both ends, creating a secure and visually appealing bound book. In many production environments, tools such as an automatic inserter/crimper are used to efficiently insert the coils.
Plastic coils are available in a wide range of diameters, pitches, and lengths, making them suitable for documents of varying sizes and punch patterns. In commercial printing, they are often preferred due to the wide selection of colors and sizes, allowing for greater customization and project alignment.
However, choosing the right plastic coil depends on several important factors, which we’ll break down below.
Determine Your Document Thickness
Plastic coil sizes typically range from 6mm (1/4") to 50mm (2"), allowing for document capacities of approximately 5 up to 460 sheets of paper (10-920 pages). The coil diameter should generally match the document thickness, with an additional 1/8" to 1/4" added to ensure proper page-turning clearance. For example, a 10mm coil is commonly used for documents of around 80 sheets, while a 12mm coil is suitable for approximately 100 sheets.
Our binding slide calculator can be used to help determine the correct coil size for your specific binding project.
The coils typically come in lengths of 12 and 36 inches, with a 4:1 pitch, meaning there are four holes per inch. This pitch is commonly used for small to mid-sized documents and is compatible with most standard coil binding equipment. However, commercial printers and binderies also request custom colors, lengths, and pitches, including 5:1, 3:1, 2:1, and 6mm options.
Consider Color Options for Your Project
Color selection plays an important role in both the functionality and presentation of plastic coil binding. Coils are available in a wide range of colors, allowing you to either match the binding to your document for a seamless, professional look or use contrasting colors to create visual impact. This flexibility makes it easy to align your binding choice with branding, design themes, or specific project requirements.
In commercial printing and production environments, color options also provide an opportunity for customization across different clients, departments, or product lines. Whether the goal is a clean, understated finish or a more distinctive and creative appearance, selecting the right coil color can enhance the overall presentation and help your project stand out.
Evaluate Coil Quality and Material
Because plastic coils are made from PVC, they offer strong durability, flexibility, and resistance to everyday wear and tear.
However, not all coils are created equal. Factors such as material quality, shape retention, and diameter consistency can significantly impact binding performance and efficiency. In fact, the quality of a plastic coil can directly influence how smoothly a binding machine operates.
Look for coils with clean, round edges, as these help ensure smooth insertion through punched pages and reduce the likelihood of snagging or misalignment. Well-finished edges contribute to a more efficient binding process and support a clean, professional end result.
Next, pay attention to coils with uniform loops, as consistent spacing helps maintain proper alignment with punched holes and allows pages to turn smoothly. Even loop formation supports better binding accuracy and helps avoid issues during insertion or use.
Prioritize coils made with strong, high-quality filament to ensure lasting durability throughout the life of the document. A well-constructed material helps the coil withstand frequent handling, bending, and everyday use without compromising performance.
Lastly, choose coils that demonstrate strong shape retention, allowing them to hold their form after binding and continued use. This stability helps maintain a neat, consistent appearance while supporting reliable performance over time.
Match Coils to Your Binding Equipment
Ensuring compatibility between your coils and binding equipment is an essential final step in achieving a smooth and efficient binding process. Different machines are designed to work with specific coil pitches, diameters, and insertion methods, so aligning your coil selection with your equipment helps prevent production issues and maintains consistent output quality. When properly matched, coils feed cleanly, insert easily, and reduce the likelihood of jams or misalignment during binding.
It is also important to consider whether your workflow involves manual or automated equipment, as this can influence the type of coil and format you choose. Some coil pitches are better suited for high-speed production environments, while others are designed for smaller-scale or more hands-on applications. Taking the time to align your coil specifications with your equipment ensures better efficiency, improved durability, and a more professional finished product.
Final Thoughts
Selecting the right plastic coil comes down to understanding your project’s needs, from document thickness and coil size to pitch, color, and overall quality. When these elements are properly aligned, you can achieve a smooth binding process and a clean, professional finished product.
If you’re unsure which option best fits your application, our experts are here to help guide you in the right direction.
***
Print finishing guides and related topics
Spooled vs Pre-Cut Wire: Which Is Right for Your Project?
Benefits of Lamination: Improve Durability, Clarity & Print Protection