Mary wanted a rigid cap for a Clover seam ripper that came with a small plastic sheath, so I called one from the vasty digital deep:
The solid model looks about like you’d expect, with a brim around the bottom to paste it on the platform:
I added a slightly tapered entry to work around the usual tolerance problems:
The taper comes from a hull wrapped around eight small spheres:
That’s surprisingly easy to accomplish, at least after you get used to this sort of thing:
hull() { // entry taper
for (i=[-1,1] , j=[-1,1])
translate([i*(HandleEntry[0]/2 - StemRadius),j*(HandleEntry[1]/2 - StemRadius),0])
sphere(r=StemRadius,$fn=4*4);
for (i=[-1,1] , j=[-1,1])
translate([i*(HandleStem[0]/2 - StemRadius),j*(HandleStem[1]/2 - StemRadius),HandleEntry[2] - StemRadius])
sphere(r=StemRadius,$fn=4*4);
}
The side walls are two threads thick and, at least in PETG, entirely too rigid to slide on easily. I think a single-thread wall with a narrow ridge would provide more spring; if this one gets too annoying, I’ll try that.
The OpenSCAD source code as a GitHub gist:
