John R. Knowles, CEO
John R. Knowles, Founder, CEO, and majority owner of Plymouth Industries, Inc., has led the company for more than 40 years, building a respected custom engineering and manufacturing organization. Guided by an entrepreneurial mindset, he has consistently driven innovation, growth, and operational excellence. Under his leadership, Plymouth Industries has developed a highly capable engineering team and a productive, solutions-focused manufacturing operation, positioned to solve complex challenges for a diverse customer base.
John’s influence extends beyond strategy and operations; he has cultivated a culture defined by integrity, creativity, and accountability. He has contributed to multiple patents and numerous original product designs, reinforcing the company’s commitment to innovation. John has instilled in his workforce a clear standard: think differently, act responsibly, and always deliver value. This philosophy is reflected in his guiding principle: “Just because you have a right does not necessarily mean it is the right thing to do; always make decisions as if the customer is in the room.”
John J. Knowles, President
John J. Knowles has been an integral part of Plymouth Industries, Inc. for more than 30 years, playing a key role in the company’s sustained growth and operational strength. As President, he leads general operations with a disciplined, systems-driven approach, using his extensive business education and experience to strengthen data controls across accounting, inventory management, costing, and production. He also directs the company’s information technology infrastructure, ensuring internal processes remain structured, accountable, and efficient. In addition, he is a minority shareholder and serves on the Board of Directors.
Mr. Knowles is deeply committed to upholding Plymouth Industries’ high standards of integrity and personally oversees all corporate charitable contributions. Guided by a belief that kindness creates lasting impact, he often reflects on the idea that “no act of kindness, no matter how small, is ever wasted,” reinforcing a culture of generosity and responsibility throughout the organization.
Michael Knowles, Vice President
Michael Knowles has been a driving force at Plymouth Industries for more than 20 years, bringing a combination of technical expertise, creativity, and customer-focused leadership. As Vice President, he oversees sales, marketing, and engineering, playing a central role in aligning customer needs with practical, high-performing solutions. His background allows him to approach challenges from multiple angles, often identifying efficient, cost-effective solutions in real time. Michael is recognized for his ability to think beyond conventional approaches, delivering value early in the design and planning phase, where the greatest impact on cost and performance is achieved.
Known for his approachable style and strong sense of fairness, Michael builds trust quickly and works collaboratively to ensure the best outcome for every customer. His service-oriented mindset and deep industry knowledge make him a reliable resource for both customers and internal teams. In addition to his leadership responsibilities, he contributes to the company’s strategic direction and serves as a minority stockholder and member of the Board of Directors.
Sales
Cory Henrickson
Account Manager
920 892-2223 Ext. 121
Tucker DeVriend
Account Manager
920 892-2223 Ext. 120
Engineering
Ken Seymour
Engineering Manager
Steve Mahloch, P.E.
Professional Engineer
Russell Preder
Lead Project Engineer
Bob Braun
Mechanical Engineer
Jordyn Grande
Mechanical Engineer
Joel Leifer
Mechanical Engineer
Keri Geib
Mechanical Designer
Zac Arbuckle
Mechanical Drafter
Purchasing
Dale Opgenorth
Buyer
Kent Thomas
Raw Material Purchasing
Marketing
Dustin Turicik
Marketing and Systems Manager
Production
Todd Meyer
Production Manager
Jeff Makovec
Quality Control Engineer
Amanda Holtz
Production Scheduler
