Stepper-Actuated Gripper

Description

The Stepper-Actuated Gripper is a 3D-printed electromechanical gripper driven by a rack-and-pinion mechanism powered by a stepper motor.
The motor’s rotational motion is converted into linear movement, allowing the gripper jaws to open and close with high precision and repeatability.

It is suitable for applications requiring accurate positioning and controlled gripping force, such as robotics, automation, and maker projects.

Typical Applications

• DIY robotic arms
• Pick-and-place systems
• CNC or automation projects
• Laboratory or test setups
• 3D-printing and maker projects

Required Parts

3D-Printed Parts

• 1× Base – structural frame and motor mount
• 1× Pinion gear – mounted on the stepper motor shaft
• 2× Gripper jaws with rack teeth – linear racks that open/close the gripper
• 4× Motor spacers – printed spacers to align the stepper motor correctly

Electronics

• 1× Stepper motor (e.g. NEMA-17)
• 1× Stepper motor driver (e.g. A4988, DRV8825, TMC2209)
• 1× Microcontroller (e.g. Arduino Nano, Arduino Uno, ESP32)
• 1× Power supply – suitable for your stepper motor (typically 12–24 V)
• Jumper wires

Fasteners

• 4× M3 × 16 mm screws – for mounting the stepper motor with printed spacers
• 2× M3 screws, approx. 70 mm long with minimum 61 mm unthreaded shaft
• 2× M3 nuts – to secure the long screws

Assembly Instructions

1. Mount the stepper motor

Place the printed spacers on the mounting holes of the base.
Attach the stepper motor on top of the spacers using the 4× M3 × 16 mm screws.
The spacers ensure the motor is at the correct height and aligned with the pinion gear.
The motor shaft should point forward through the opening in the base.

2. Install the pinion gear

Slide the pinion gear onto the stepper motor shaft.
Ensure it is firmly fixed so it cannot slip.

3. Install the gripper jaws

Insert one M3 screw (approx. 70 mm, min. 63 mm unthreaded shaft) through both gripper jaws:

• Push the screw through both jaws
• Secure with an M3 nut on the opposite side
• Tighten until the jaws are stable but still able to move smoothly

Ensure the pinion gear meshes properly with the rack teeth of the jaws.

4. Test movement

Slowly rotate the stepper motor by hand or drive it at low speed:

• The jaws should open and close evenly
• No binding, skipping, or slipping should occur