The Nyloc nut atop that modified quilting foot requires more grip than fingers can provide:

The “precision” wrench I adapted to that nut works for small adjustments, but for larger ones it’s easier to take the foot off and spin this knob:

It has a hex opening in each end that fits the nut, with a through hole for the bolt. The top looks exactly like you’d expect:

The bottom needs a bit of support:

The solid model shows off the support in color:

The OpenSCAD source code doesn’t have many surprises:

// Quilting foot knob // Ed Nisley KE4ZNU January 2013 use <knurledFinishLib_v2.scad> //- Extrusion parameters must match reality! // Print with +1 shells and 3 solid layers ThreadThick = 0.20; ThreadWidth = 0.40; HoleWindage = 0.2; function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); Protrusion = 0.1; // make holes end cleanly //---------------------- // Dimensions KnobOD = 20.0; KnobLength = 25.0; KnobSides = 12; DiamondLength = KnobLength/3; DiamondWidth = DiamondLength/2; DiamondDepth = 1.0; NutOD = 7.0; // across flats! NutLength = 6.0; ScrewOD = 4.0; DoSupport = true; //---------------------- // Useful routines module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2); FixDia = Dia / cos(180/Sides); cylinder(r=(FixDia + HoleWindage)/2, h=Height, $fn=Sides); } module ShowPegGrid(Space = 10.0,Size = 1.0) { RangeX = floor(100 / Space); RangeY = floor(125 / Space); for (x=[-RangeX:RangeX]) for (y=[-RangeY:RangeY]) translate([x*Space,y*Space,Size/2]) %cube(Size,center=true); } module Knob() { rotate(180/Sides) { difference() { // cylinder(r=KnobOD/2,h=KnobLength,$fn=KnobSides); render(convexity=10) knurl(k_cyl_hg=KnobLength, k_cyl_od=KnobOD, knurl_wd=DiamondWidth, knurl_hg=DiamondLength, knurl_dp=DiamondDepth, e_smooth=DiamondLength/2); translate([0,0,-Protrusion]) PolyCyl(ScrewOD,(KnobLength + 2*Protrusion),6); translate([0,0,(KnobLength - NutLength)]) PolyCyl(NutOD,(NutLength + Protrusion),6); translate([0,0,-Protrusion]) PolyCyl(NutOD,(NutLength + Protrusion),6); } } } module Support() { color("Yellow") for (Seg=[0:5]) { rotate(360*Seg/6) translate([0,0,(NutLength - ThreadThick)/2]) cube([(NutOD - 1*ThreadWidth), 2*ThreadWidth, (NutLength - ThreadThick)], center=true); } } //---------------------- // Build them! ShowPegGrid(); Knob(); if (DoSupport) Support();

Mary likes it… and thinks I’m being silly. She’s right, of course.