Knob, AC gauge set manifold

thingiverse

I bought this AC gauge set ~15yrs ago from a local auto parts store, made by InterDynamics. Don't think they make this particular model anymore. Came with plastic knobs, but the high-side knob (originally red color) broke due to heat and age. Had to use a crescent wrench to open the high-side valve, did this for years grrrrr... Well now that I have a 3D printer, let's solve that problem! Here's the result. The new knob is the same diameter, width and has the same shape as the original. The recess for the screw is smaller ID. Functionally it's a perfect match. Two different knob designs are included, pick what suits your aesthetic. The square hole fits over either valve shaft, which is 6mm square outside dimension. 3D printed knob has 6.4mm internal dimensions accordingly, to compensate for print tolerances. Circular thru hole will accommodate the original M4 screw, pan head or flat heat type. Recess might be too shallow for socket head cap screw, please check. I included STEP, SCAD and FreeCAD files for remixing. Note: I'm a FreeCAD noob, please forgive any transgressions. In images below, knob with "Open" is the original injection molded part. Now if I could just find replacement plastic gauge covers I'd be set! Might need to print a screw ring for a small disc of acrylic, hmmm.....