Finger Assembly

This is the instructions for one finger, so it is repeated 4x *

** Note that for the index, middle, and ring fingers the 3D printed joints are identical (named Finger Joints), but the lengths are different for the pinky (Pinky Joints).

---

Materials

Tools

• Tweezers

• Razor Blade or Scissors

• 1.5 mm Allen Key

3D Printed Parts

Part Name	Total Quantity
Finger Joint 1	3
Finger Joint 2	3
Finger Joint 3	3
Pinky Joint 1	1
Pinky Joint 2	1
Pinky Joint 3	1

Hardware (Total)

Part Name	Total Quantity
Dowel	8
M2 x 4 mm Screws	16
Extension Springs	8
String	Roll

---

Instructions

Quantities are per finger per step.

1. Attach String to Joint 3

Part Name	Quantity
String	~ 1.5 ft
Finger Joint 3 / Pinky Joint 3	1

Put both ends of the string in the holes.	Pull them through	Taking both ends of the string tie a slip knot using the following steps.
Tighten the slipknot and trim the blue end.	Push the knot into the joint. This may require tweezers.	Feed the string to the other side of the pulley.

2. Attach String to Joint 1

Part Name	Quantity
String	~ 1.5 ft
Finger Joint 1 / Pinky Joint 1	1

Pull string through hole.	Tie slip knot (same as previous step).
Tighten the knot and feed it through the joint.	Pull the string through the joint.

3. Connect Joints with Dowels

It is easiest to route the string before putting together the dowels.

It can also be done after, but may require the help of tweezers.

Part Name	Quantity
Dowels	2
Finger Joint 1 / Pinky Joint 1	1
Finger Joint 2 / Pinky Joint 2	1
Finger Joint 3 / Pinky Joint 3	1

The joints should be able to move freely. If there is friction/ they are not moving, you may have to drill/file the outer holes so that the joint moves freely like in the video.

---

4. Attach Extension Springs

Part Name	Quantity
Extension Springs	2
M2 x 4 mm Screws	4
Finger Joint 1 / Pinky Joint 1	1
Finger Joint 2 / Pinky Joint 2	1
Finger Joint 3 / Pinky Joint 3	1

---

You should have four assembled fingers at this point.