High Frequency Grinding Spindles

CAPITAL's Motorized Grinding Spindles

Capital is manufacturing precision motorized spindles for over 15 years. We emphasis on quality, accuracy and on time delivery which makes Capital's Spindles the best choice for your production needs.

We specialize in precision fitting custom built AC Induction motors to the spindle shaft. Precision balancing of these units provides high accuracy and high-speed capability. A temperature controlled assembly and inspection area and state-of-the-art coordinate measuring machines.

Horsepower ­ Heat Dissipation

Motor horsepower (HP) is a function of the size and the RPM of the motor. The larger the motor, the greater the horsepower at a given RPM.

Motors that generate greater heat loss can be cooled with a fan that blows air over the motor. These motors are classified TEFC (totally enclosed fan-cooled.) When even greater horsepower is required in a smaller package, TELC (totally enclosed liquid-cooled) motors are used. These motors are cooled by circulating liquid around the motor.

Capital has many years of experience in the design and application of precision motorized spindles. For more information you may please contact


Variable Frequency Drives

Capital supplies motorized spindles for any speed up to 75,000 RPM. To operate at speeds other than 900, 1200, 1800 or 3600 RPM, a variable frequency drive is required. Variable frequency drives must be carefully matched to the motors they drive. Motors and variable frequency drives have pre-determined volts-to-hertz ratios, and these ratios must match for a successful application. Speed control can be integrated into your machine control for ramp-up, ramp-down and adjustment. This can be included in your machine program code or as an electrical control switch or dial

Spindle Lubrication

High speed spindles require special bearing lubrication. Capital's air/oil lubrication systems injects precise amounts of oil at controlled intervals for optimal bearing life and minimum heat generation. Utilizing only fractions of a drop per cycle means no environmental oil mist concerns. In addition the high air pressures used provide maximum protection against contamination of the spindle.