• O.D. & I.D. Grinding

  • O.D. & I.D. Taper Grinding

  • O.D. Profile Grinding

  • Diamond Roll Form Grinding

  • Hard Chrome Grinding

  • Magnetic Rotor Grinding


  • O.D. up to 12.0" diameter x 42.0" long

  • I.D. from .38" min to 12.0" max diameter

  • I.D. Grinding up to 8.0" in Depth

  • Complex Configurations

  • Extremely Close Tolerances

Learn More about Cowan

Cowan specializes in Magnetic Rotor Grinding for aerospace and commercial applications.  Contact us to find out more.


The Cowan Grinding Story

When Frank Cowan started Cowan Precision Grinding in 1968 in Burbank, California, he had a 1956 Cincinnati Universal Grinder and a plan to offer the best possible precision grinding service to the burgeoning Southern California aerospace industry. From these humble beginnings, the company has grown into one of Southern California’s top sources for precision grinding. Today, more then fifty years later, Cowan Precision Grinding offers extremely close-tolerance O.D. and I.D. grinding; plus O.D. and I.D. taper grinding, O.D. profile grinding, diamond-roll form grinding and hard-chrome grinding per BAC 5032.

frank cowan
Founder Frank Cowan in 1968

"When you’re working on a job with thousands of dollars already invested, you’d better know exactly what you’re doing. If you don’t, you’re out of business in a hurry."

In 1980 when Phil Cowan took over the business, he already had a decade of precision grinding experience under his belt. Phil met the challenges and steadily grew the business, acquiring the company’s first Mitsubishi CNC grinder in 1995. From that point on, Cowan Precision Grinding has pursued the perfect combination of advanced technology and old-fashioned craftsmanship. The result is a level of quality and reliability rarely seen in the precision manufacturing industry today. “When you’re working on a job with thousands of dollars in material and labor already invested,” explains Phil, “you’d better know exactly what you’re doing. If you don’t, you’re out of business in a hurry.”

phil cowan
"Ask Phil Cowan about job planning & how to prepare your parts for grinding."

Today, Phil Cowan, Jr. is following in his father’s footsteps, learning and perfecting the craft of precision grinding from the ground up. With more than twenty years under his belt, Phil Jr. is carrying on the Cowan family tradition of quality and craftsmanship began by his grandfather over five decades ago. With eight state-of-the-art CNC and eight manual grinding machines, and a team of seasoned professionals with years of hands-on grinding expertise, we can grind outside diameters up to 12.0” and up to 42.0” in length, and inside diameters from .375” to 12.0”, and up to 8.0” deep with absolute precision and accuracy.

For more than fifty years Cowan Precision Grinding has earned its reputation for excellence and dependability. That is why dozens of local precision manufacturers, as well as many worldwide high-tech firms, trust Cowan Precision Grinding with their precision grinding requirements. When it comes to precision I.D. and O.D. grinding, there isn’t much that Cowan can’t do. As Phil likes to say, “If it can fit in our machines, we can grind it.”

Find out why Cowan Precision Grinding is the first choice for manufacturers both large and small. Contact us and let us show you what we can do.


What's New at Cowan Grinding

cnc surface grinding

New Toyoda GL4 O.D. Angle Head Grinder

New 2015

We’ve recently replaced one of our grinders with a new Toyoda GL4 O.D. Angle Head Grinder.  This new grinder features: a 12.0” diameter x 20.0” long capacity, up to a 4.70” diameter wheel, lateral location devices, size gaging, and custom wheel profiling.  In order to offer our customers the best possible level of quality, value, and service, we invest in the latest grinding technology and equipment to keep your costs down and deliver your parts on time.

At Cowan Precision Grinding, you’ll find the most advanced grinding technology available anywhere, and we use it to offer our customers the best quality and service in the business.  You can count on it.

We specialize in magnetic rotor grinding for aerospace & commercial.

Call Us at (818) 361-3512