After cutting down the Y axis screw for the CNC gantry router project we had a short piece of 3/4 inch Acme leadscrew remaining that was just long enough to drive the Z-axis. Buying an ACME tap to make a single nut was out of the question as they are normally over $100. So we set about heat forming a threaded nut from some bits of scrap UHMWPE (Ultra High Molecular Weight Poly Ethylene). We made the nut in two halves with the intention of shimming them in the final build, this will allow for slight adjustment while keeping backlash under control. According to Wikipedia, UHMWPE has a melting point of around 145°C and a co-efficient of friction that approaches Teflon. Up next is short video of the thread forming followed by some drive testing with the cordless drill.