This week, we found that the 3D-printed plastic was harder to thread than expected, thus requiring a change in approach. We briefly considered using threaded inserts, which are hollow cylinders with a threaded interior that could be glued into their design to allow our existing threaded rods to screw in and to attach securely. We also thought about printing a hollow rod instead of a filled rod, as that might make it easier to thread. However, after discussion, we realized that the rod would probably just snap under pressure whilst using the stepper motor. 

Then, we realized that we could probably dismantle the old stepper motor slider and repurpose the internal threading. However, as a backup plan, we discussed the potential buying of threaded inserts that would match our existing threaded rods. For the plan on threaded inserts, we confirmed that we needed to buy threaded inserts compatible with an M5 rod, as this matched the threading on the rod that we had already purchased. Then, we considered possibly using hot glue to secure the threaded insert to the printed bracket used to press down on the pipette buttons. 

However, the existing stepper motor slider proved to be extremely difficult to dismantle, as many of the metal components were linked together in a way that made it impossible to separate without damaging the components. However, we managed to find a T8 screw and nut block set, which essentially referred to a vertical screw rod with a cube, i.e. the nut block, attached to this rod. The pitch, or the distance between threads, was 2mm while the lead, or the distance the nut travels in one full revolution along the rod, or with each turn, was 8mm. Our bracket could be designed to be attached to this nut block, such that it could press down on the pipette buttons. However, to complete the design of the stepper motor slider, we needed to design a two-rod-esque contraption that connected the top and bottom of the screw rods, the nut block, and our stepper motor together, such that movement of the bracket would be aligned.