How to Purchase the Right Three-Knife Trimmer
By: Bruce Peterson, President, Colter & Peterson
The origin of the 3-knife trimmer dates back to the early 1900s, but the general surge of these types of machines began in the mid-1950s with the introduction of the Krause Wohlenberg A43 series, which replaced the Sheridan as the previous industry standard. Although nearly a century has come and gone, the basic principles of 3-knife trimming have remained relatively unchanged. Unfinished product, usually book blocks, is taken into the machine, clamped, trimmed on all three sides and finished product is ejected out. The major improvements have been in speed, computerization and makeready features.
Class of Machine: Handfed, Offline or Inline?
Although any type of 3-knife trimmer can be combined with just about any adhesive binder, the binder usually dictates which make, model and style of trimmer should be used. When choosing a 3-knife trimmer, first resolve whether you need a light duty handfed 3-knife trimmer, a semi-automatic offline machine or one that is fully integrated into an automated, inline binding solution.
Hand-fed and offline 3-knife trimmers require operators to feed product directly into the machine and are appropriate for companies with handfed perfect binding equipment. For those with high speed binders in the 4,000+ book per hour range, an inline 3-knife trimmer is the right solution. Conveyer belts are necessary to deliver freshly glued book blocks directly from the binder to the 3-knife trimmer. If you have any doubt which class of 3-knife trimmer you need, a phone call to your dealer will quickly provide the advice you need to make an informed decision.
Production Workflow Considerations
Besides budget and existing machine concerns, also consider the product and turnaround needs of your customer base. For instance, if you frequently bind thin books approaching the 1/8” or thinner range, or books with a combination of loose, glued or folded forms, then a machine with hydraulic clamping offers greater stability and ultimately better quality.
If your customers feed you a bevy of short run jobs (fewer than 300 pieces), a hand-fed machine is sufficient. If there’s a lot of size and thickness variability, you probably should consider more of an “on demand” style 3-knife trimmer with speedier set-up times. Horauf, Accutrim and Challenge offer machines that fit this bill.
Used, Rebuilt or New?
The next consideration is whether to purchase a used, rebuilt or new 3-knife trimmer. If you’re installing a state of the art Wohlenberg Master S or Champion S perfect binder, any decision other than a new 3-knife-trimmer is suspect. Short of this, unfortunately, there’s usually no easy answer because a lot of factors should be considered. If you’re replacing a 3-knife trimmer on an existing binder, then factor in your binders’ age, annual usage, maintenance history, expected future life and current business need.
Your clients’ needs are important. If you’re servicing the financial report printing market, downtime is heavily penalized and peace-of-mind reliability is worth paying for. Buy new. If your client base is more understanding about occasional production downtime, a used machine may be the smart purchase. Rebuilt trimmers fall somewhere in the middle.
More Compact, User-Friendly On-Demand Three-Knife Trimmers
The greatest improvement in 3-knife trimming technology has been in the on-demand segment. Computer touch screens, servomotors, automatic calibration and program storage are no longer only available in the realm of the state-of-the-art high speed machinery.
More companies are ignoring conventional wisdom and choosing short run 3-knife trimming solutions, regardless of their existing binder. While this behavior is somewhat unanticipated, part of the justification could be the publishing industry’s drive to reduce inventory by increasing it’s percentage of on demand titles.
Tricks of the Trade
No matter how tempting, don’t purchase a 3-knife saddle stitching trimmer in the hopes of converting it for use on a perfect bounder. Old or obsolete machinery could also cause headaches because it can be difficult to get serviced.
Machines that are worn out will not consistently perform well. Pay close attention to “wear areas” of a used machine, which can greatly affect final cut quality. The importance of working with a reputable dealer that puts your needs first cannot be overstated.
There’s no such thing as a “scratchless” 3-knife trimmer. Regardless of brand, make or design, all trimmers require experienced, qualified operators who know the tricks of the trade to produce good work on time. For example, there are ways to minimize damage to books during the trimming process. Low tech solutions such as taping the table or slip sheeting and handling books with white gloves are commonplace.
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No 3-knife trimmer will take a badly produced book block and transform it into a thing of beauty. If your binder forces too much glue into the spine resulting in an unsightly “nail head” appearance, or if the book is printed cross-grain and the spine is wavy, only a magic wand can create an award winning piece. In the end, your finished product can only be as good as the starting material.
Bruce Peterson is President of Colter & Peterson, the largest independent distributor of paper cutters and paper handling equipment in North America. Employing more than 75 people in four locations, Colter & Peterson specializes in every facet of paper cutter and perfect binding acquisition and ownership, including maintenance and repair, machine sales, safety and productivity upgrades, surplus machines and more. Contact Bruce at (800) 932-0780 x206 or bruce@colterpeterson.com.
