These quilting pin caps are slightly longer than the previous version and, due to the M2’s smaller nozzle, have slightly thinner single-thread walls. Because Slic3r does a better (although not ideal) job of path planning than Skeinforge, it’s easier to create an array of the caps in the solid model than to manually add duplicates in Slic3r:
They look like egg cases from Prometheus:
Fill with silicone caulk on waxed paper and they look even more like that:
Fast-forward a few days, rub off the excess caulk, trim off a few blobs, and they’re ready for presentation:
In use, they look about like you’d expect:
The pin caps I made from a 5 gallon bucket’s O-ring gasket didn’t work out well, as the plastic didn’t like being poked with pins and put up a stiff resistance. Silicone caulk has exactly the right consistency.
When Mary ramps up a full-scale quilt, we’ll need a few hundred of the things. The commercial version has dropped to 40 cents each, which makes all this worthwhile.
The OpenSCAD source code:
// Quilting pin caps
// Ed Nisley KE4ZNU April 2012
// January 2013 - modify for Slic3r and M2
//- 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
ID = 5.0;
OD = ID + 2*ThreadWidth;
Length = 8.0;
Sides = 8;
CapArray = [6,6]; // XY layout of caps
CapsOC = OD + 2.0; // OC spacing
//----------------------
// 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 PinCap() {
rotate(180/Sides) {
difference() {
PolyCyl(OD,Length,8);
translate([0,0,-Protrusion])
PolyCyl(ID,(Length + 2*Protrusion),8);
}
}
}
//----------------------
// Build them!
ShowPegGrid();
translate([(-CapsOC*(CapArray[0] - 1)/2),(-CapsOC*(CapArray[1] - 1)/2),0])
for (i=[0:(CapArray[0] - 1)],j=[0:(CapArray[1] - 1)])
translate([i*CapsOC,j*CapsOC,0])
PinCap();
They seem to work pretty well…
