RobotShop M100RAK V4 Modular Robotic Arm Kit (No Electronics)

RobotShopSKU: RB-Rbo-85
Manufacturer #: M100RAK-V4

Price  :
Sale price £675.65

Tax included

Included in this bundle


  • Four Degree of freedom (4 DoF) modular robotic arm
  • ~1Kg lifting capacity at full reach (640mm / ~29.53in)
  • All metal gears
  • General mounting plate for mounting an end-effector (no gripper)
  • Servo controller and power supply sold separately

The RobotShop M100RAK V4 Modular Robotic Arm Kit is one of the most affordable and versatile “intermediate sized” all-metal robotic arms on the market. The arm has a maximum (suggested) reach of just over 640mm without the addition of an end effector (gripper) and can lift about 1Kg at this extension. The closer the weight is to the body, the more the arm can lift. The M100RAK includes all brackets, hardware and 4x Hitec HS785HB RC servo motors. Although the functionality is similar to previous versions, the V4 uses a different design, different brackets and the mounting hole pattern is different.

The M100RAK is intentionally modular, and the design provided in the product description and the assembly guide is only one of many possible configurations. Joints and brackets can be flipped or rotated as needed, and parts from the GoBilda system easily added to make custom designs. The center of each joint and tube is hollow, so wiring can be internal. Easily customize your arm by drawing and creating 3D printed shells using the CAD files provided below.

M100RAK V4 - Side View

Most robotic arms are either too small for regular applications, or too expensive to be used as development platforms by hobbyists. The M100RAK is intended to be the perfect size for most robotic arm applications since it is roughly the length of an adult human arm, and still powerful enough to lift a decent payload. Note that each servo can potentially draw up to 1.8A under full load, so you will need a 6V power supply capable of ~5A continuous and ~10A peak. .

Warning: The arm contains open gears and is very powerful. Please take every precaution to ensure no objects (especially fingers) get caught in the gears. Should you have this fear, we suggest adding a bent cardboard or plastic cover over each joint. Keep out of reach of children.


  • Robotic arm: With the addition of a gripper, a standard robotic arm can be used for many different projects.
  • Computer-controlled camera mount: The basic arm includes a metal mounting plate which can easily be used to mount a standard camera.
  • 3D image capture: Adding a distance sensor to create a complex 3D scanner. Adding a variety of sensors to a robotic arm
  • Router-based CNC machine: Mount a handheld router and create a manual or CNC controlled router arm for experimentation
  • Scale human arm: The length of the shoulder joint to the elbow joint is almost the same length of an adult's humerus bone, while the length from the elbow to the wrist joint is almost the same as an adult's Ulna. There are two main degrees of freedom missing in the arm to make it closer to that of a human: a rotation joint within the “humerus” and a rotation joint within the “ulna”.

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