Hand Construction

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Required Parts

The construct the hand you will require both 3D printed parts and machined parts. You can find the 3D printing tutorial here and the Machining Tutorial here. All required files for part creation can be found here. For the hand you will need to make the following parts:

Right Hand

3D Printed Parts:

5x Finger Plate

1x Right Thumb Knuckle

2x Knuckle Plate

1x XL-320 Servo Holster

3x Finger Tip

Machined Parts:

1x Hand Plate

Additional Parts:

11x XL-320 Dynamixel Servo

54x White XL-320 Pegs

24x Grety XL-320 Pegs

2x 4mm x 30mm screws

4x 4mm x 36mm screws

2x 4mm x 5mm screws

8x 4mm nuts


The first thing to be done is remove the screw in the center of each XL-320 Dynamixel. Then assemble the fingers as shown in the diagrams below. The pegs are differentiated by color in the diagram so be careful to use the white pegs and grey pegs in the proper areas. There are 4 fingers total for both hands, two per hand.

Finger assembly.PNG Finger assembly top view.PNG


Below is the instructions for the Right Thumb. The steps for assembling the Left Thumb are identical but use the Left Thumb Knuckle instead of the Right Thumb Knuckle. Image comparisons for the Left and Right hand are shown further below. The Thumbs require two 4mm x 30mm machine screws to hold the XL-320 dynamixel to the XL-320 Servo Holster as shown in the diagram below.

Right thumb assembly.PNG Right thumb top assembly.PNG

Hand Construction

Below are the instructions for constructing the Right Hand. The Left Hand follows identical instructions but has the Hand Plate reversed. An example of both are shown further below. For the first step of hand construction, we use four 4mm x 36mm machine screws and four grey pegs to mount the 2 XL-320's to the hand. These servos hold the fingers and allow them to splay. The servos are secured by nuts as shown in the figure below:

Hand step 1 assembly.PNG

Next we attach the thumb. We mount it with the base attached to the opposite side than the servos. To construct the left hand, we simply mount the thumb and servos on opposite sides of the right hand configuration, but the locations of the screws remain the same. This is described in more detail later on. The Thumb is mounted using two 4mm x 5mm screws and two grey pegs as shown in the picture below. We show the bottom and top side of the hand assembly below:

Hand step 2 assemble.PNG Hand step 2 back.PNG

At this point the hand should currently look like the image below. This is the right hand with thumb and both splay servos mounted:

Hand step 2.PNG

Next we attach the fingers to the hand. First remove the screws from the two splay dynamixels, then attach them through the knuckle plates as shown in the diagram below:

Hand step 3 assembly.PNG

Now our Right hand is complete. The completed right hand is shown in the diagram below:

Right hand step 3.PNG

To construct the left hand simply follow the above steps but mirrored for the thumb and hand. Analyze the pictures below to make the proper adjustments:

Right hand.PNG