The New Hotness

The auto-rewind spindles for PolyDryer boxes fit a variety of spools, but recessed hubs like this require a pair of washers to center the spindles:

Filament spool washers - recessed hub — Filament spool washers – recessed hub

They’re laser-cut, although you could print them easily enough:

Filament spool washers - recessed hub - installed — Filament spool washers – recessed hub – installed

The size for that particular spool:

OD = 80 mm
Flange side ID = 51 mm
Nut side ID = 43
Thickness = ¼ inch, near enough

Other spools required a 3 mm shim on the flange side to sit centered in the PolyDryer boxes. Those are basically identical what you see above, with a 72 mm OD matching the flange.

The PETG-CF filament arrived on cardboard spools, which are apparently the new hotness:

Filament spool washers - printed — Filament spool washers – printed

The 56 mm spool ID requires adapters on both sides, with the flange side getting a 4 mm shim:

Filament spool washers - printed shim - flange side — Filament spool washers – printed shim – flange side

That skootches the spool over against the 1 mm shim on the nut side:

Filament spool washers - printed - nut side — Filament spool washers – printed – nut side

It would be possible to modify the auto-rewind spindle diameters to suit, if you were a dab hand with Fusion360, but the variety of hubs around here tells me a set of cheap adapters & shims makes more sense.

You should not assume anything will fit the spools you have, no matter how much they resemble what you see above.

The OpenSCAD source code as a GitHub Gist:

	// Polymaker PolyDryer auto-rewind spool washers
	// Ed Nisley – KE4ZNU
	// 2025-05-20

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build]


	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 334;

	$fn=NumSides;

	ID = 0;
	OD = 1;
	LENGTH = 2;

	Gap = 5.0; // Build separation
	SpoolWidth = 20.0; // Show separation

	FlangeOD = 72.0; // auto-rewind spindle
	FlangeHubOD = 50.5 + 1.0;
	NutOD = 77.0;
	NutHubOD = 42.0 + 1.0;


	//———-
	// Define Shapes

	module EryOneCF(Side = "Flange") {

	SpoolID = 56.0 – 1.0;
	SpoolSideThick = 3.0;

	if (Side == "Flange")
	tube(4.0,od=FlangeOD,id=FlangeHubOD,anchor=BOTTOM) // flange side
	position(TOP)
	tube(SpoolSideThick,od=SpoolID,id=FlangeHubOD,anchor=BOTTOM);

	if (Side == "Nut")
	tube(1.0,od=NutOD,id=43.0,anchor=BOTTOM) // nut side
	position(TOP)
	tube(SpoolSideThick,od=SpoolID,id=NutHubOD,anchor=BOTTOM);

	}



	//———-
	// Build things

	if (Layout == "Show") {
	left(SpoolWidth/2) yrot(90) EryOneCF("Flange");
	right(SpoolWidth/2) yrot(-90) EryOneCF("Nut");
	}

	if (Layout == "Build") {
	left((FlangeOD + Gap)/2) EryOneCF("Flange");
	right((NutOD + Gap)/2) EryOneCF("Nut");
	}

view raw PolyDryer spool washers.scad hosted with ❤ by GitHub

The New Hotness

3D Printer Filament Spool Washers