Focus ST Shift Knob - Functional Reverse Lockout

thingiverse

Description: I tried printing out another shift knob design when mine broke, but none of them on here appeared to fit a focus ST. I spent some time completely redesigning it from scratch. I took measurements of the original and made sure there was enough clearance so that the reverse lockout remained functional. After several iterations of each part, I finally nailed down the design. It includes a lead pellet/powder holder to mimic the weight of the original and incorporates a M12x1.25 locknut for a secure hold. Assembly/Print Instructions: I recommend using something with more heat resistance than PLA. I only used it for the inlay while everything else is ABS or ASA. PETG or Nylon would work as well. All of my parts were printed with 4 perimeters and 30% infill. The threads might be too much of an overhang for these filaments depending on your settings. I printed mine with supports to be safe. Make sure you have have your supports tuned before you attempt this though. When printing the inlay scale the X and Y axis by 103%. It will help provide a tighter fit once assembled. See the print orientations below. Lower - threads facing up (with supports) Upper - threads facing down (with supports) Inlay - flat face down (scale X and Y by 103%, might need to adjust this depending on how your printer is tuned) Pellet holder - flat/chamfered side down Ring - either flat face down Once printed, verify that the upper and lower parts will screw together completely. If not, there is either material stuck in the threads or something about about the slicer/tuning that is throwing off the designed fit. If it works, unscrew the upper and press the locknut (I used a Hillman M12-1.25 metal locknut) into the lower part. Fill the pellet holder with whatever you want to use as weight and insert it into the cavity above the locknut (chamfered side down). Take the inlay and press it into cutout of the upper piece (a small amount of glue won't hurt here). Finally, place the ring around the lower part's edge and screw the upper part down tight. The pellet holder file was an afterthought to hold lead pellets or powder. I used some from shotgun shells, but you can find powder online as well. Only fill it to the brim or else the upper part of the knob will not be able to screw all the way down.