About Trotter Manufacturing

Delivering the precision you need.
On time & on budget.

Trotter Manufacturing (TMI) was established in 1999 by Earl Trotter when he purchased K&M Screw Products in Rockford, IL. K&M was exclusively a turned components producer until 1985 when it produced its first valve spool. Since then, TMI has developed deep industry expertise, leading-edge processes, and superior equipment technology to become a world leader in valve spool manufacturing.

Today, TMI principals Skip Trotter (President) and Jeff Cassaro (COO) lead an experienced and talented team in meeting our customers’ critical needs for high-quality spools and turned parts.

TMI specializes in both tilt-style spools and spools with intricate internal features in addition to standards, regularly satisfying customer demands for rapid prototypes. Our strength is our ability to meet customers’ support needs from prototype through launch and ongoing production with short lead times, excellent quality and reliable delivery. We utilize SPC to control critical areas of our processes and can provide PPAP’s upon request.

TMI has made significant equipment investments to build our state-of-the-art blanking & grinding equipment and quality tools & systems. Everyday, TMI demonstrates the capability to hold grinding tolerances of 1.5 micron (.00006″). Our associates strive for perfect quality and delivery every day in our Continuous Improvement culture, along with a multi-talented workforce who can perform many operations to meet our customer’s ever-changing needs. Customer service is everyone’s job TMI!

A Global Presence


In 2006, to support a customer’s global manufacturing expansion, TMI embarked on the journey to become a global company, constructing a plant in Bangalore, India. Two years later, TMI and Rollon Hydraulics formed a joint venture called TMI Rollon, with their first spool shipped in April of 2009.





Since the inception of TMI Rollon, capacity has been expanded and the joint venture now has the capability to produce valves spools and turned parts for other customers as well.

This dual-continent manufacturing foot print enables TMI to offer competitive pricing and excellent quality anywhere in the world.