Derek Korn

Derek Korn joined Modern Machine Shop in 2004, but he has been writing about manufacturing since 1997. His mechanical engineering degree from the University of Cincinnati’s College of Applied Science provides a solid foundation for understanding and explaining how innovative shops leverage advanced machining technologies, equipment and processes to their advantage. Derek also manages the magazine's annual Top Shops benchmarking survey, which enables U.S. machine shops to see how their technology- and business-related key performance indicators stack up against the country's leading machining businesses.

Posted by: Derek Korn 18. January 2019

Top 3 Questions about the Top Shops Benchmarking Program

Top Shops logo

This year marks the ninth edition of Modern Machine Shop’s annual Top Shops benchmarking program. Here are the top three questions I am asked about the program:

1. What is it?

Top Shops starts with a survey. The survey, which is now live at through the end of February, enables shops of all types and sizes to see how they compare against leading U.S. machining businesses in terms of machining technology, shopfloor practices, business strategies and human resources/workforce development.

The survey prompts for equipment, process and financial information, and includes a few open-ended questions. It does not ask for specific financial figures, such as gross sales or net income. Instead, it asks you to supply financial measures as percentages, including net income per gross sales, annual sales growth rate and capital equipment expenditure per gross sales. Our thought is that this will encourage greater participation from shops that are not inclined (or allowed) to provide financial data. Nonetheless, all survey responses will remain confidential.

2. What is a “Top Shop?”

Once we receive the survey responses and scrub the data to remove outlier responses, we establish a Top Shops benchmarking group. That group represents the top 20 percent of shops based on points assigned to select survey questions in each of the four survey categories (i.e. they are the “Top Shops”). That way, you can compare your key performance indicators with the nation’s most successful shops and see what equipment and strategies they are leveraging to their advantage on the shop floor and in the front office.

3. Why should I participate?

You will benefit in various ways. For example, you will receive a free custom report comparing your responses to quantitative questions to all other survey participants. A data plot for each question provides a general performance summary for your company. The report also includes your shop’s overall survey rank among the surveys received and lists key metrics for which your company is particularly strong, is on par with others, or perhaps should be targeted for improvement.

Top Shops includes an Honors Program, too. The Honors Program highlights successful participating companies in each of the survey’s four aforementioned sections, identified by responses to select questions and follow-up interviews by me. Those shops are profiled in Modern Machine Shop and on MMS Online. In addition, we offer a prize package that includes a large Top Shops banner that can be displayed in your shop, T-shirts, hats, toolbox magnets and so on. We also provide winners with a press release template that can be modified and sent to various press outlets to get the word out about winning the award.


This article was adapted from a piece first appearing on MMS Online.

Posted by: Derek Korn 8. January 2018

Top Shops Survey Now Live, Participate for Custom Report

This blog post originally appeared on MMS Online.

an example of a custom Top Shops Report

We’re on to the eighth edition of our annual Top Shops benchmarking survey. In fact, the online survey is now live and will remain open through the end of February. In short, the survey enables shops of all types and sizes to see how they compare against leading U.S. machining operations in terms of tactics and metrics in categories including machining technology, shopfloor practices, business strategies and human resources/workforce development. 

Last year was the first time we offered custom reports that rank a participant’s responses to the survey’s quantitative questions against other applicable participants. We’re doing that again this year. Learn more about the reports, and visit our Top Shops Zone to access information from past surveys.

Posted by: Derek Korn 7. September 2017

The Top Shops 2017 Benchmarking Survey Results Are Now Available

2017 Top Shops Executive Summary

This blog post is adapted from a post that originally appeared at MMS Online. 

It’s hard to believe we’re on our seventh edition of our Top Shops benchmarking survey. The results of that survey are available in the 2017 Executive Summary, which compares the top-tier benchmarking group’s data to the other shops that participated. Here are two interesting tidbits I gleaned about types of equipment used by a majority of the shops in this year’s benchmarking group:

  • 32 percent use Swiss-type lathes, which is up from 19 percent last survey. Although screw-machine shops were the first to adopt multifunction CNC Swiss-type lathes, an increasing number of “traditional” shops are considering this machining platform to, in some cases, produce complex parts complete, reducing setups, secondary operations and work-in-process.
  • 37 percent have additive manufacturing/3D-printing capability, which is up from 19 percent during the last survey. Virtually all of those shops use this capability for prototyping, but 74 percent of them also use it to 3D-print tooling and fixturing for their own use on the shop floor.

The Executive Summary includes much more about the types of machining and business strategies being applied by leading U.S. machining businesses as well as key performance metrics they’re attaining. Give it a read. It could be that information could help direct your own continuous improvement efforts.

Posted by: Derek Korn 7. July 2017

What Is Low-Frequency-Vibration (LFV) Turning?

This article originally appeared as a blog post for Modern Machine Shop titled “Video: What’s Low-Frequency-Vibration Turning?”

In most cases, turning operations involve continuous cuts in which the tool remains engaged with the material from the time it starts the cut to the time the cut is completed. Marubeni Citizen-Cincom has developed what it calls low-frequency-vibration (LFV) technology, which is available on its L20 sliding-headstock Swiss-type lathes. This technology purposely oscillates the cutter in the Z axis in time to the rotation of the barstock. At times, it actually brings the cutter completely out of the cut.

The company says the advantage of this programmed oscillation is that the intentional air cuts break the chips into small pieces so they can be readily expelled, minimizing the problems of spiraling chip entanglement around the workpiece known as “bird nesting.”

This strategy is said to be particularly effective in controlling chips/preventing bird nesting when turning materials such as copper, plastic, Inconel and stainless steel—a challenging task for conventional turning operations. Additional benefits are said to include increased cutting tool life, minimized build-up on cutter edges, and reduced heat generation and power consumption. In addition, the same type of cutting tools a shop would use for conventional turning can also be used for LFV turning, the company says.


The video above demonstrates the concept, showing the changing amount of cutter engagement with the material as it oscillates. To make a 90-degree square shoulder, the oscillation stops and the tool is fed in a conventional manner.

The LFV concept also can be applied to drilling and grooving operations. In the case of the latter, the grooving tool oscillates/plunges in and out normal to the barstock circumference in the X axis.

Posted by: Derek Korn 13. January 2016

Yes, You Can Turn Parts on These Five-Axis Machines

 This article was originally published in Modern Machine Shop's December 2015 issue under the title "Technology for Turning on a Five-Axis Machine."


A rotary table balance control system enables 600-rpm turning of non-symmetric parts weighing as much as 8,818 pounds.

A rotary table balance control system enables 600-rpm turning of non-symmetric parts weighing as much as 8,818 pounds.

Five-axis machine tools combine linear XYZ travels with A- and B-axis rotation to enable the machining of five sides of a part in one setup. Some are used to perform 3+2 operations, whereby the part is rotated and locked into an angled position, and the machine essentially performs a three-axis operation with the part oriented in that way. Others can execute more complex, full-contouring five-axis operations that use simultaneous linear and rotational motions to pass a cutting tool over a contoured surface.

(This Techspex blog post goes into more detail about five-sided vs. five-axis machining.)

In some cases, attachments can be used to enable these machines to perform turning operations, too. However, when static turning tools are mounted directly into a machine’s main spindle, as they typically are, the shock loads common to turning can eventually lead to spindle bearing damage.

This has spurred Burkhardt + Weber, part of Industrias Romi SA, to develop its MCT line of five-axis machines. The MCT series includes five machine models that can turn parts ranging in diameter from 11.8 to 110 inches and weighing as much as 8,818 pounds at a maximum rotational speed of 600 rpm (workpiece capacity when turning is not performed is 15,432 pounds). These machines feature the following integral design elements said to enable productive turning, even for non-symmetrical parts, without causing damage to the spindle bearing system:

Turning tool adapter. With the conventional approach of inserting a static turning tool into a five-axis machine’s spindle, the spindle rotor is often clamped to the spindle’s outer housing in order to lock it in a stationary position to protect against possible turning shock loads. Lighter cuts are also typically performed to prevent bearing damage, but this leads to lower productivity.

The MCT five-axis machine line features a turning tool adaptor that mounts to the spindle housing via a zero-point clamping mechanism. This isolates the machine’s main spindle bearing from the shock of turning operations compared to other designs in which a static turning tool is inserted into the main spindle.

The MCT's tooling adapter.

Conversely, the MCT machines feature an automatically exchanged tooling adapter that mounts to the spindle housing via a zero-point clamping mechanism, isolating the spindle bearings from the shock of turning operations. The system uses four clamping cylinders located 9.84 inches apart and supplies 26,400 pounds of clamping force to secure the turning tool adapter to the spindle housing. Turning tools can be automatically loaded and unloaded into the adapter just like a milling tool from the machine’s ATC.

Table balance control. Because parts to be turned on a five-axis machine often aren’t symmetric, the MCT machines feature a compensating balance-control system. After a part or pallet is loaded and securely clamped to the machine’s table via a mechanical spring-based safety system, a balancing cycle is automatically performed at 80 rpm using sensors to measure rotational forces. Afterwards, a display on the machine’s CNC shows the location and amount of counterweight required to bring the system into balance. Turning operations can proceed once balance quality is confirmed after another 80-rpm test cycle.

Thermal isolation system. Torque motors in rotary tables used for turning on a five-axis machine generate a good deal of heat, causing unpredictable expansion and contraction of a machine’s frame that can adversely affect accuracy and repeatability. Rather than using complex temperature-compensating software algorithms and sensor feedback, the MCT machines remove heat surrounding the table and frame with an actively controlled cooling system, stabilizing the frame by maintaining a consistent temperature. In addition, the company developed a non-contact, 16-channel hydraulic rotary sealing system for the machine line’s 600-rpm tables that does not generate heat due to friction or wear of mating seal surfaces common to
conventional systems.

The MCT series includes the MCT 750, MCT 800, MCT 900, MCT 1000, MCT 1200 and MCT 1250. Investigate these machines' specs for free with Techspex


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