Technical Articles

Mechanical Binding: Nothing Lies Flatter

Published in New England Printer & Publisher

by Frank Shear

For products that must lie flat-as-a-board, there is no substitute for quality mechanical binding. Saddle stitching is a low cost alternative, but this binding method isn't appropriate for many projects. Layflat adhesive binding is a terrific option, but even its pages don't lie perfectly flat.

Mechanical binding is a great solution for many book projects. Imagine how poorly a perfect bound calendar would look dangling from a wall. Not too appealing, right? For some calendar styles, saddle stitching is a reasonable alternative, but stitches just don't have the same elegance as great looking mechanical binding elements. Properly executed mechanical binding is truly a marriage of form and function.

Computers, high tech products, complicated equipment and many other products need manuals that lie flat. Any computer user who has tried to read a perfect bound manual while typing on a keyboard knows that perfect bound products are hard to use in these circumstances. Most perfect bound books will snap shut unless heavy pressure is applied, which breaks the spine and causes pages to fall out. Mechanical binding is a time-tested solution that solves this problem.

Mechanical Binding Options

There are four primary types of mechanical binding styles: Wire-O™ (Wire-O is a registered trademark of James Burn International), plastic spiral, spiral wire and plastic comb. Each has its own set of advantages and disadvantages.

Wire-O is generally considered the Cadillac of mechanical binding. It is an elegant, durable and versatile binding style that has been popular for decades, yet never looks dated. Bound pages open without a "step-up", which makes Wire-O an appropriate choice for books with crossover images. Wire-O elements are available in a wide variety of standard colors and if necessary, can even be specially ordered to match any PMS color, as long as minimum quantities are satisfied. Since Wire-O can be highly automated, it is an economical choice for long runs. Wire-O bound book blocks may be cased in either hard or soft covers which makes beautiful, functional products. Although Wire-O certainly is strong, one downside is that if stepped on, Wire-O binding elements are permanently damaged.

Plastic spiral is popular for use in products such as children's books, high tech manuals and cookbooks. Plastic spiral elements are very durable and spring back to their original shape even after being crushed. For products to be used by children or placed on fine furniture, plastic spiral doesn't scratch and is generally considered to be safer than Wire-O. Like Wire-O, plastic spiral elements are available in a wide variety of colors and sizes. Although plastic spiral can be highly automated, as of now these machines aren't common, so long runs usually aren't economical. Since plastic spiral bound pages step-up when opened, avoid crossover images whenever possible.

Spiral wire bound products have neither the elegance of Wire-O, nor the contemporary appeal of plastic spiral. Although inexpensive, spiral wire's popularity appears to be declining. Unless a really thick gauge of wire is used, spiral wire binding isn't as strong as Wire-O because a single spiral wire coil is comprised of less wire than Wire-O's "double loop" design. And, like plastic spiral, spiral wire's pages step-up.

The fourth horseman of mechanical binding - plastic comb binding - is the most different. Unlike the other three, plastic comb binding doesn't open 360°, so it isn't an attractive choice for books that need to be held in one hand. In addition, plastic comb binding elements can be imprinted, but this advantage is quickly lost since the others can have printed reversible or fully concealed wrap-around cover styles. Although plastic comb binding is useful for very thick books, many designers think that plastic comb elements have a dated look, resulting in declining product popularity.

Cover Styles

There are many cover style choices for mechanically bound products. Split back (two-piece) covers are least expensive and most common cover style. When spine printing is necessary, reversible and one-piece spine styles are good choices. Semi-concealed and cased-in styles have an appearance that most looks like traditional books.

Perfectly formed Wire-O bound books have double-looped "teeth" that close with a slight overbite holding pages firmly in place. Make sure that the seam of the wire rests between the back cover and the last page of the book block. For plastic spiral products, the crimped ends of the coil should never extend past the diameter of the coil itself.

Production Planning

Since many mechanical binding projects involve a lot of job components, examine a preflighted sample prior to the production run. Since good binderies do this anyway, your request shouldn't affect your delivery date. Save time and money by working with your bindery to ensure the right binding element is selected and that your complicated projects can be automatically collated and trimmed.

Before having your bindery order Wire-O or plastic spiral binding elements, get a bulking dummy made on the exact paper you will be using. Paper bulk varies between different brands of paper and even between different lots of the same paper. If the binding element is too tight, production will be slow and the pages will not easily turn. If the binding element is too loose, the pages will be dwarfed and the whole book will look ungainly. Changing sizes isn't much of a problem for binderies that stock many spools of wire in common colors as a courtesy to their customers. Be safe and ask your bindery what their wire stocking policy is in advance.

If you deliver a pre-collated mechanical job to a bindery, it's very important that each page is the same size. If not, you risk incurring hand punching, which is neither time nor cost effective. If your job has different page sizes, don't pre-collate it. For example, consider a mechanically bound book with alternating half- and full-size sheets. For a project of this type, a bindery would be able to punch all the short sheets first; the full-size ones second; and then automatically collate the job - as long as it wasn't pre-collated. Minimize your headaches by letting your bindery professional guide the mechanical binding process from design through shipping.

When selecting your Wire-O binding supplier, make sure your choice has high-speed inserting machines with both "jaw" style and "flat" close tools. For some difficult projects, jaw-closing machines are preferable because they force the wire to conform to the shape of the tool itself - yielding perfectly formed binding elements. Flat-closing machines have very quick make readies and in many cases offer comparable quality to jaw closing machines. For maximum flexibility, your bindery should have both styles of machine.

Avoid Punching Problems

Punching into copy is an easily preventable, but all too common, problem. Before you commit ink to paper, ask your bindery how much margin they need to clear the punched holes for your project. In general, most 3:1 (three holes per linear inch) Wire-O projects require a 3/8" spine margin. For 2:1 Wire-O books bulking over 1/2" thick, allow at least 1/2" margin.

Punching tabbed pages is possible, but there must be empty space for "pushers" on punching machines to reach a non-tabbed back edge of the paper. Punching four-pagers is possible, but make sure that your bindery OKs the design first. Punching Mylar or other acetate-reinforced sheets is fine, but if the substrate is 100% acetate, then your bindery should place a paper-based carry-sheet underneath each lift to maintain cleanly punched holes. Punching other materials such as Pajco, laminated paper, board and plastic is usually possible, but check with your bindery first.

For Wire-O books with odd-sized spines, make sure that your bindery properly centers the punched holes along the spine edge because off-center books don't look right. However, odd-sized plastic spiral books may require the plastic spiral elements to be slightly off center. For advice, ask your mechanical binding company about this situation early in the design process.

Packing Issues

Packing is critical. It's important that mechanically bound books are staggered (wire left, wire right, wire left, etc.) so that the binding elements don't rest on other books, creating unwanted indentations and marking. Carton selection is very important. For example, standard boxes that fit normal 8 1/2" x 11" products won't perform well for books needing staggered packing. Cramming books into wrong-sized boxes is always a recipe for disaster, as is packing books too loosely. If uncoated tin wire is used, then marking problems are likely to occur. For books that are identified as likely candidates for transit marking, slip sheeting, shrink wrapping or foam packing should be used.

More Things To Know

Embossing or debossing can shorten the width of a cover and should be compensated for.
Die-cut window registration to ink is different for mechanical binding, perfect binding and saddle stitching.
Laminating, UV coating, aqueous coating and dry trap varnish can help prevent scratching, picking or feathering covers with heavy ink coverage. Inline press-applied varnish rarely does.

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Mechanical binding is a rapidly growing segment of the book binding industry because it offers a world class solution for products that must lay flat. Hop on the mechanical binding bandwagon, plan your jobs wisely and delight your customer. After all, isn't this what we are really after?

Frank Shear is President of Seaboard Bindery, a service-oriented trade bindery located in Woburn, Massachusetts. His company specializes in offering high quality perfect and layflat adhesive binding, saddle stitching, Wire-O™, plastic spiral, laminating and other bindery solutions. Call Frank at (781) 932-3908.