Centerless Grinders: Making Parts Round, Straight, and True

Sep 23, 2022
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Centerless grinders are one of the manufacturing industry’s most indispensable machine tools. Without them, parts like shafts, pistons, camshafts, and valve spools would be less accurate. They’d also cost a whole lot more. Fortunately, we don’t live in a world like that. As you’ll see, high-quality centerless grinders are readily available. The question then becomes, how do they work? And more importantly, what should a person look for when buying one?

Basics of Centerless Grinders

We’ll tackle the basics first. Centerless grinders earned their name because there’s no need for a center or drive dog as with a cylindrical grinder. This means they can grind 12-foot bar stock as readily as they can small pins and rollers. Moreover, they can generate complex profiles by simply dressing the desired shape into the grinding wheel. This process is called plunge or infeed grinding. It relies on an end stop to eliminate axial movement of the workpiece while grinding.

The alternative is through-feed grinding. As its name implies, the workpiece in this scenario travels from one side of the wheel to the other. When done, it exits the back side of the machine. In either case, a regulating wheel sits directly opposite the grinding wheel. It controls the workpiece’s rotational speed and forces it against the wheel. Sitting between and slightly below each is a work rest that supports the part during grinding.

Checking the Centerless Grinder Boxes

As with practically all machine tools, stability is critical. A one-piece, Meehanite cast iron base is best for absorbing vibration. It also helps assure accuracy. The spindle should have similar qualities. For example, the KCG-series cylindrical grinders from  utilize a forced lubrication system. This arrangement creates a hydrodynamic oil film that surrounds the bearings, further dampening vibration. Add to that three-point bearing support at each end of the spindle. Together, this design provides the highest precision and heaviest workpiece loads possible. Finally, look for a variable vane pump. It ensures consistent spindle oil circulation and highly accurate hydraulic wheel dressing. These pumps also offer years of trouble-free operation.

For more information, reach out to the experts at Kent USA. We’ve been building machine tools of all kinds since 1979. We offer four sizes of centerless grinder, with wheel sizes up to 24-inch diameter and 30-horsepower spindles. Moreover, our machines are compact and easy to operate. Simply put, we know grinding, machining, EDM, and sawing, and our thousands of satisfied customers will attest to that.

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