by Anna C. Massey, Gateway Bookbinding Systems Ltd.

If you aren’t already doing plastic spiral binding, you really should be. Plastic spiral has become one of the most popular mechanical binding choices in today’s market. The durability of plastic spiral, the vast array of available colors from which to choose and advancements in the automation of the coil binding process have caught the attention of most binding consumers.

Base compound makes a difference

Most plastic spiral manufacturers produce coil using a PVC (polyvinyl chloride) compound. The required colorant is added during the extrusion process, at which time the PVC and colorant pellets are melted and mixed. The extruded filament is wound as a single strand profile onto spools.

Different profiles are produced for particular coordinating coil diameters. The spooled filament then is put through the forming process and manufactured into the specific diameter, pitch and length of coil that is required.

Although most plastic spiral binding utilizes this PVC base compound, what goes into that compound can differ between manufacturers. Every compound will have different levels of additives that can and do affect the finished product. Additives such as impact modifiers help insure the coil is durable and will maintain its shape. Lower grade materials are not, however, as strong and may contain fillers that bulk up the product with no actual benefits. Lead-free and phthalate-free spiral binding also are very important features, especially when producing children’s books.

All coil is not created equal

Different coil manufacturers can and do use different profiles or gauges of filament to produce the various coil diameters. A 10mm coil may be produced with a filament of 2.0mm (.080″). Others may use a thinner filament, like 1.8mm (.072″) or even 1.5mm (.060″).

If you are price shopping for a potential coil supplier and are strictly looking at the cost on the printed price list, you may not be comparing “apples to apples.” If a manufacturer is using a very thin filament to produce its product, the price list will look more appealing because less material is being used to produce the coil. It is important to know what profiles of plastic a coil supplier uses to make its various coil diameters.

Plastic spiral binding that is very thin can cause problems during the insertion process. Plastic spiral that is too thick also can cause difficulty when inserting, which will reduce production numbers.

Recommendations can and should be made based on the book thickness, with the proper punch-hole size and shape being discussed. The type of coil inserting equipment being used also makes a difference.

A sharp lead edge on the coil is another important factor when the coil is running through the punch holes. It also has been proven that a “reverse cut” on the larger diameter/thicker profile coils will aid with coil insertion even further. Talk to the supplier to understand the options that are available.

Pitch – the most misunderstood term

You’ve heard the term and have probably been asked, “What pitch do you use?” It’s a simple five-letter word, but it is – without a doubt – the most misunderstood term within the industry.

The dictionary definition of pitch, as it pertains to machinery, is the distance between corresponding points. In the world of plastic spiral binding, pitch is easiest to illustrate through punch patterns. There are a number of different pitch options available, and they are not all the same.

Unlike double-loop wire binding with the simple 3:1 and 2:1 pitch choices or comb binding with the standardized rectangular-shaped 19 holes on the 11″ edge, coil binding is a little different.

The various pitch choices for coil binding have come about because of a combination of originating European manufacturers (that work with the metric system) and North American manufacturers that utilize traditional Imperial measurements.

For simplicity’s sake, remember 1″ equals 25.4mm.

.2475″ Pitch – This is fast becoming the pitch of choice. This hole pattern fits the best on the common 11″ and 8.5″ (as well as the European A4 and A5) binding edges without the need to pull pins or trim to center. At first glance, the .2475″ pitch looks a lot like four holes within the inch, but it is indeed different than the traditional True 4:1. The .2475″ pitch also is most commonly available with a 5x4mm oval punch hole.

True 4:1 Pitch (also known as .250″ or ¼” pitch) – True 4:1 is probably the most common of pitches. Many North American equipment manufacturers work with this pitch. It literally means that there are exactly four punch holes within every 1″. Although a common pitch, it does mean that punch pins need to be pulled in order to center this pattern on the 8.5″ or 11″ edge.

6mm Pitch – Common amongst European equipment manufacturers, the 6mm pitch does not mean six holes per inch. It means that there are 6mm from the center of one hole to the center of the next hole. It equates to four and a partial hole within every 1″.

5:1 Pitch – Although very common 20 years ago, the 5:1 pitch (five holes per inch) rarely is utilized these days because it really only worked well for thin projects. Any book thicker than 3/8″ became a challenge to bind with such tight spacing and a typically smaller punch hole. There even is a metric 5mm pitch that is close to a 5:1 spacing. Few equipment manufacturers offer these options any more.

Wider 3:1 or 2.5:1 Pitch – These wider pitch options are literally worded. The 3:1 pitch means that there are three holes within every 1″ measurement. The 2.5:1 means just that – 2 1/2 holes per 1″. These pitch choices commonly are used when binding thicker books. The wider spacing makes coil insertion much easier. It also is recommended that the punch hole itself be a larger 6.5×5.5mm oval shape. This larger punch hole provides the coil more room to wind its way through. That size of punch hole can and does improve productivity by a good 40 percent.

There even are more pitches available – like a .312″ pitch or an 8mm pitch. These were common with metal spiral binding and sometimes still are used with plastic spiral.

The right pitch for a binding job primarily depends upon two factors – the book’s thickness and length of the binding edge. For example, even though the .2475″ pitch fits best on an 11″ binding edge, if a job with a 10 7/8″ binding edge is being produced on automated equipment and trimming is not an option, then a 6mm pitch would be better suited for the job.

Talk to the plastic spiral binding supplier. It is the supplier’s job to make sure customers are set up with the most productive equipment available – within budget – that will enable efficient and successful handling of coil binding needs.

Anna C. Massey is director of marketing for Gateway Bookbinding Systems Ltd., Winnipeg, MB, Canada. For more information, call 800.665.7884 or visit www.plastikoil.com.

by Jen Clark, The Binding Edge

Mechanical binding can be a cost-effective way to create bound documents that open flat and can offer 360-degree rotation. With the right tools, companies can have professionally punched and bound documents produced in-house. Determining if a project needs to utilize plastic coil or wire, though, starts with knowing how the finished product should look.

Since plastic coil comes in a variety of colors, it often can be matched to a theme or to a company’s corporate identity. Plastic also is more durable, said David Spiel, co-owner of Spiel Associates, Long Island City, NY, “although some feel that wire is more aesthetically pleasing.”

Plastic spiral binding, single strand wire binding and double loop wire binding all are mechanical types of binding, explained Anna Massey, sales and marketing manager with Gateway Bookbinding Systems Ltd., Winnipeg, MB, Canada. Single strand wire binding typically is done with an automatic process – the metal wire being formed and wound through the punch holes to complete the book. With double loop wire binding, the pre-punched book is “hooked” onto the open wire and then the wire is closed to contain the sheets. With plastic spiral binding, the pre-formed coil is wound through the punch holes and the ends crimped to complete the process.

The popularity of one type of binding over another pertains more to the types of projects being bound, Massey said. “For example, calendars and desk calendars often still are done with double loop wire because when the item is opened, the double loop wire provides for even registration between the open sections,” she said. “Plastic spiral binding seems to have become the number one choice for student agenda books because of its safety and durability factors, as well as vast color selection.”

In the US especially, plastic coil has become the binding method of choice, Spiel added. “There are many states that bar the use of wire in school books or books for children,” he said. “Designers in the US tend to get excited over the range of colors with plastic coil.”

Added Massey: “Wire binding still often is viewed as the “strong” binding, because it is produced from metal. It’s an interesting perception because it is very easy to bend and distort wire binding – even just during transport. Plastic spiral is much more durable, but viewed – in some overseas markets – as the weaker of the two products.” Even though there has been a spike in the use of plastic coil in the European market, “double loop wire is much more popular elsewhere in the world,” Spiel said.

All types of binding have their pros and cons, Massey said. “Metal spiral and double loop wire easily are distorted and bent when shrinkwrapped or packed. Plastic spiral is more durable and will bounce back and hold its shape if or when pressure is applied.” When a straight registration of the open book is required, double loop wire is the choice, she noted. “Plastic spiral will “drop” when opened – as the opened book’s left side follows the angle of the coil.”

Spiel agreed, adding the left side’s “drop” is about one-half-of-a-hole lower. “That is the nature of spiral binding, but pages from left to right line up perfectly with a book bound with double loop wire. This is important with maps and ledgers,” he said.

Metal and double loop wire have limited color choices available, while plastic spiral comes in over 50 different colors, Massey said. “Plastic spiral also is a smoother product, especially when in the hands of children. Metal and double loop wire have sharp edges that can snag,” she said. “From a production standpoint, metal spiral always has been viewed as a more automated process, but plastic spiral has seen a tremendous development in this regard. There are systems putting out 25 plastic spiral bound books a minute.”

Companies that are producing documents in-house should consider outsourcing the job based on the size of the job and equipment capabilities. A project’s complexity and turnaround time also are important factors to consider. “If you only have manual equipment, you may only be able to bind 50-100 books per hour,” Spiel said. “A manual set-up will require two operators to achieve this output. If you have to pay two employees to do the work, it would be prudent to send large runs out.”

Spiel and Massey agreed that binding thick documents sometimes can be challenging. “You can bind up to about 1?” thickness with double loop wire, using 1¼” diameter wire,” Spiel said. “With plastic coil, you can bind up to 2″ in diameter and about 1¾” in thickness.” He suggests using an automatic machine to bind thick books, “such as the Sterling Coilmaster that can bind up to 50mm in diameter,” he said.

Gateway’s specialty is the PLASTIKOIL® plastic spiral, which is manufactured up to 2″ in diameter. “That can handle up to 460 sheets of a 20lb bond book,” Massey said, noting some manufacturers go even larger. Gateway also offers the PLASTIKOIL Binding Stick, which is a connecting device to join multiple plastic spiral bound books. “With the Binding Stick, there really are no limitations,” she said.

When it comes to plastic spiral binding, there are a number of options available for pitch – the distance or spacing between the loops of coil. The key is to match the pitch of the coil to the punch pattern. If a document is punched with a 4:1 pattern, then it needs a 4:1 coil. Incompatibility between pitch and punch pattern can affect productivity. “With plastic spiral binding, a wider pitch of 3:1 or 2.5:1 always is recommended for coil diameters larger than about a 30mm,” Massey said. “That is a book thickness of 1″ or more. A larger oval hole in these wider pitches also is recommended. This wider pitch and larger punch hole provides the coil with more room to find its way and thus will improve productivity as much as 45 percent.”

Double loop wire traditionally uses a 3:1 round or square hole for thinner books. A wider 2:1 pitch with a slightly larger round or square hole is used for thicker books. “Plastic spiral often was done with a 4:1 pitch round hole, but we’ve seen a shift over the past 10 years to a more logical .2475″ pitch 5x4mm oval hole,” Massey said. “The .2475″ pitch fits on the common 8.5×11″ and European A4 and A5 sheet sizes – without the need to pull punch pins and center.”

Partially opening a thick book while driving the coil through the punched holes helps a lot, Massey said. “The coil is driving through only half the book’s thickness at a time,” Massey noted. Gateway also offers a “reverse cut” coil in the larger diameters to help aid the insertion process. “The reverse cut lead edge smoothly funnels its way through the punch hole in comparison to the standard cut lead edge – a great advantage especially when binding thicker books.”

The Binding Edge would like to thank Anna Massey, sales and marketing manager at Gateway Bookbinding Systems Ltd., Winnipeg, MB, Canada, (www.plastikoil.com) and David Spiel, co-owner of Spiel Associates, Long Island City, NY, (www.spielassociates.com) for contributing to this article.