While CADing I found the original design of the finger joint to be clunky. The 3d printed joint body (yellow) holds a pin (orange) which is held in place with a 1/8 thick piece of laser cut acrylic sheet (red). This acrylic piece is then screwed in. The pins added unnecessary costs because they where made from High-Speed M2 Tool Steel reamer stock (McMaster-Carr part number 3023A366). They cost about $1.71 each, but that $1.71 is adding up. Coming in at about $80 for all the pins. These pins are used to connect the metacarpal plates, so I originally thought I could use them again for the fingers, but there is a better option.

I didn’t realize it, but we can get 0-80 screws 1 inch long. These cost only $8.22 for a pack of 50 and take much less assembly time. It is unfortunate that we have to redo the CAD for each expanding joint in the finger, but this design makes much more sense.