One of the three big knobs on my wife's sewing machine broke. This version while it doesn't have any markings should fit the bill. (Might be compatible with other Janome models too). V4 should be dimensionally accurate, I only made v5 of the STL because I learned later that my 3D printer was over extruding making the part too tight to fit. The Fusion360.f3d file is included should you want to modify the knob in anyway prior to printing.