HC series Electromagnetic Chuck
The HC series is Magna-Lock USA's rotary electromagnetic chuck series.
Often found as the workholding on Mattison rotary grinders among other brands, the HC series features three types of standard chucks, with many different customization possibilities.
Popular uses:
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On surface grinders
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On lathes
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On cylindrical grinders
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For small or thin workpieces
Magna-Lock USA electromagnetic chucks
Type I
A rotary electromagnetic chuck with a 7 ½” diameter bronze center cover plate to provide access to the collector ring and brush holder assembly.
This is the most standard model and most popular of rotary chucks that are manufactured by Magna Lock USA.

Type II
A rotary electromagnetic chuck with a removable center cover designed to carry the magnetic holding derived from the chuck’s innermost coil to provide holding action down to a 2 ¼” diameter.
The height of this chuck is greater than a Type I chuck and there is an entirely different construction used around the innermost chuck body ring. Because of this, it is not possible to convert a Type I rotary chuck to a Type II rotary chuck.

Type III
a rotary electromagnetic concentric ring chuck designed especially for certain vertical spindle rotary table surface grinders. The collector ring for this type of chuck is a separate assembly that is mounted down on the machine spindle completely external to the chuck.
Accessibility to the collector ring and brush holder is through a removable cover in the machine itself, so this type of chuck does not have the typical removable center cover and provides magnetic holding down to about 3” diameter in the center.
