Building a Robotic Arm — Part 2

Building the mechanical assembly

In the first part of this series I listed the parts required to build the mechanical assembly for a robotic arm. You might remember my delight is discovering that no instructions were included! Yes, I’m one of those silly people who assemble IKEA furniture and then look at the instructions to see if I did it correctly. (Surely having parts left over just means I have assembled it more efficiently, right…) Realising that most people won’t want to spend an hour staring at a pixelated image of the assembled arm on the amazon product page to determine the best order in which to assemble it I decided to create some instructions.

Assembled robotic arm

There’s a few ways you can put these arms together. I opted to copy how the arm was assembled according to the pictures on the amazon product page.

A quick note on fasteners

Before we begin there are 4 types of fasteners used in this robot arm kit. To avoid any confusion in this guide I will refer to them by a number as shown in the image below.

Nuts and bolts
  • Machine screw #1 is used to attach the metal servo horn to the servo and also to attach the servo horn to the metal parts of the robotic arm. These screws came with the metal servo horns and were not part of the robotic arm kit. Some equivalent screws were included with the arm kit but I decided not to use them as they were shorter.
  • Bolt and nut #2 are used to connect all the non-moving metal parts together.
  • Bolt and nut #3 are used with a bearing (not pictured) to connect the 4 main moving joints of the robotic arm.
  • Bolt and nut #4 are used to attach the body of the servos to the robotic arm.

#1, #2, and #3 all have the same thread which I believe is an M2 thread. #4 appears to have an M4 thread.

Right, with that out of the way let’s get going! Read More