On Demand Three-Knife Trimmers Making Deepest Market Cut
By: Bruce Peterson, President, Colter & Peterson
The origin of three-knife trimmers dates back to the early 1900s but the general surge of these types of machines actually began in the mid-1950s with the introduction of the Krause Wohlenberg A43 series which set the standard for offline trimmers. Sheridan had previously written the book on in-line three-knife trimmers back in 1934.
Hand-fed, In-line or Offline?
Although any type of three-knife trimmer can be used with any type of binder, the binder usually dictates which make, model and style of trimmer that should be used. When choosing a three-knife trimmer, the first question to ask is whether the customer is looking for a hand-fed, in-line or an offline trimmer.
The in-line trimmer has the ability, with the use of conveyers, to be put in-line for perfect binding for hands-free operation while a hand-fed trimmer requires product to be fed into the machine. Customers typically know based on their runs or binder, what type of trimmer their project requires.
The second consideration in purchasing a used, rebuilt or new three-knife trimmer is based on the customer’s budget with new high-speed machines costing well into six figures.
Weighing Options
Besides budget concerns, customers looking for a hand-fed machine should also weigh the trimmer’s available options before making a decision.
For instance, if customers are trimming short runs with a variety of size changes, they should lean towards a more on demand trimmer that’s a makeready model such as those made by Horauf, Accutrim or Challenge CMT 330.
Hand-fed trimmers for short runs are usually paired with offline trimmers. If the customer is trimming thin products or ones with loose, glue or folded signatures, then a machine with hydraulic clamping offers an added benefit over other mechanical design trimmers because this provides greater flexibility for that type of product.
More Compact, User-Friendly
The latest trend as far as three-knife trimmers go has been on demand trimmers. The biggest evolution on three-knife trimmers has been the electronic set-up features including computer touch screens, servo motors, automatic calibration and program storage. Customers desire more compact, user-friendly trimmers that anyone can operate.
More companies are doing shorter runs on three-knife trimmers these days regardless of the type of trimmer they’re using. Trimmers with on demand capabilities are popular among publishers who are now ordering smaller batches of printed materials. Some publishers are producing over a million books a month with the average length run of one and ¾ books. Larger runs have gotten smaller because everybody wants on demand.
While three-knife trimmers originated in the early 20th century, the basic principles of the machinery have remained relatively unchanged. Product is taken into the machine, the product is clamped, trimmed on all three sides and the finished product is ejected out. The major changes in the equation have been the speed, computerization and makeready features of the trimmers.
Tricks of the Trade
Mistakes often occur when customers purchase a three-knife trimmer designed for saddle stitched books in hopes of using it on perfect bound books which are not designed for that purpose. Buying old or obsolete machines also spells trouble for these trimmers since they are difficult to get serviced.
Machines that are worn out will not cut a consistently sized and sure finished product because the control of this capability is generally given up to the machine. Experts advise paying close attention to wear areas of a used machine which can affect final cut quality.
It’s important to understand that there’s no such thing as a scratch less three-knife trimmer and that regardless of the brand, make or design, all trimmers require the operator learning the tricks of the trade to produce a product of acceptable quality to meet the customer’s demand.
As Good As It Gets
There are ways to minimize any slight damage to books being trimmed such as taping the table, slip sheeting and handling the books with white gloves. No three-knife trimmer will take a bad book and cut it well because it’s all driven by the binder. If you give the binder a bad book to begin with, no trimmer is going to make up for those mistakes.
If the binder produces an inconsistent book with nail heads where the spine thickness varies with crooked covers, the trimmer cannot compensate for those issues. That applies even more to on an inline trimmer because all control is given up to the machine. In the end, the finished product is only as good as what you give the three-knife trimmer to work with and who’s operating the machine.
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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.
