Stepper motors with large bore hollow shafts

Moon’s Industries has created a family of stepper motors with large-bore hollow shafts.

Moons large bore hollow shaft stepper motor

There are five basic motors, ranging from 36 x 36mm (7 or 12mm bore) to 60 x 60mm (27mm bore):

size (mm) 36×36 42×42 57×57 60×60
Shape round square square square square
Bore (mm) 7 12 16 22 27

All of the motors measure 21mm from front to back, plus 8mm of shaft protrusion.


In each case there is a standard and a higher holding-torque variant, for example: the 42mm 200mNm HS17HX7L4100 and its higher torque same-size cousin the 220mNm VHS17HX7L4100. These both have a 16mm bore.


Torque figures across the family vary from 170mNm to 425mNm.

Moons HS-VHS hollow shaft stepper polariser driver applicaton“The large bore diameters of Moon’s hollow shaft stepper motors opens up many design possibilities, allowing for the integration of linear transmission shafts, cables, air flow, liquids, or even [light] beams directly through the centre of the motor,” according to the company. “When paired with a harmonic gearbox, these hollow shaft motors deliver output torque levels nearly matching those of our solid shaft motors.”

Moons HS-VHS stepper motor bayonet flange

Shaft ends can be a plain tube, have two slots for bayonet-style torque transmission (right), a flange with four threaded holes in an axial direction, or a flange with four radial threaded holes.

Applications are foreseen in robotics, semiconductor manufacturing, industrial automation and security systems.

Moons HS-VHS hollow shaft stepper scanner applicaton

Optical use is emphasised, with the motor rotating a polariser for beam passing down the bore in one example (above left), or the motor used with a right-angled prism to convert an axial beam into a radial scan (left – imagine line-scanning the inside of a pipe).

Steve Bush

Steve Bush is the long-standing technology editor for Electronics Weekly, covering electronics developments for more than 25 years. He has a particular interest in the Power and Embedded areas of the industry. He also writes for the Engineer In Wonderland blog, covering 3D printing, CNC machines and miscellaneous other engineering matters.

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