The New Hotness

Setting up the Makergear M2 to print TPU (eSun 95A) involved a cold pull to get the remaining PETG out of the nozzle, some manual flushing, then printing test cubes to figure out a reasonable speed / temperature combination:

Makergear M2 - first TPU test cube — Makergear M2 – first TPU test cube

A 10 mm solid cube came out overstuffed and the first 20 mm cube lacked enough infill to hold its top up, but the third cube looked surprisingly good at 230 °C and 30 mm/s with 15% 3D Honeycomb infill:

Makergear M2 - TPU test cubes — Makergear M2 – TPU test cubes

With that settled, I conjured pairs of soft (-ish) jaw pads for the far-too-many metal spring clamps having worn out their vinyl pads:

Spring clamp jaws - installed — Spring clamp jaws – installed

Those were the first attempt and worked well enough to suggest nicely rounded endcaps instead of flat cylinders:

Spring Clamp Jaws - show view — Spring Clamp Jaws – show view

Unlike the first version, they now build standing on their rectangular clamp jaw opening:

Spring Clamp Jaws - slicer preview — Spring Clamp Jaws – show view

Those two groups have different lengths (1 inch and 1-⅛ inch) with PrusaSlicer combining the OpenSCAD program’s output.

The as-built pads are essentially un-photographable:

Spring clamp jaws - group build — Spring clamp jaws – group build

TPU is tough enough to make the single-layer brim un-tearable, but they’re easy enough to separate & trim with scissors. Even the 5 mm brim has a tenuous grip on glass + Suave hair “spray” applied from a dropper bottle, so I should try a BuildTak sheet that’s been on the to-do pile for far too many years.

Similarly, TPU is flexy enough to make a precise fit unnecessary: push firmly to force the pads onto the jaws and you’re done.

The OpenSCAD source code as a GitHub Gist:

	// Spring clamp replacement jaw pad
	// Ed Nisley – KE4ZNU
	// 2025-04-26

	include <BOSL2/std.scad>

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

	Ends = "Round"; // [Flat,Round]

	Sets = 1;

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 234;

	WallThick = 2.0;

	CushionOD = 10.0;
	CushionStem = 10.0;

	JawAngle = 60/2; // just for Show

	JawWidth = 1.000*INCH; // clamps are hard-inch sizes: 1.0 and 1.125

	Jaw = [1.5,50,JawWidth]; // roughly one jaw

	Gap = 2.0;

	$fn = 234;

	//———-
	// Define objects

	//—–
	// Clamp jaw

	module Clamp() {

	up(WallThick)
	cuboid(Jaw,anchor=BOTTOM+BACK);

	}

	module Pad() {

	difference() {
	union() {
	cyl(d=CushionOD,h=Jaw.z + 2*WallThick,anchor=BOTTOM,
	rounding = (Ends == "Flat") ? 0 : CushionOD/2);
	cuboid([Jaw.x + 2WallThick,CushionStem,Jaw.z + 2WallThick],
	rounding=WallThick/2,anchor=BOTTOM+BACK);
	}
	Clamp();
	}
	}

	//———-
	// Build things

	if (Layout == "Clamp") {
	Clamp();
	}

	if (Layout == "Show") {
	for (i = [-1,1])
	right(i*(CushionOD + Gap)/2)
	zrot(i*JawAngle) {
	Pad();
	color("Silver",0.5)
	Clamp();
	}
	}

	if (Layout == "Build") {
	for (n = [0:(Sets – 1)])
	for (i = [-1,1])
	right(i((CushionOD + Gap)/2 + n(CushionOD + Gap)))
	up(CushionStem) back(Jaw.z/2) xrot(90)
	Pad();
	}

view raw Spring Clamp Jaw Pads.scad hosted with ❤ by GitHub

The New Hotness

Metal Spring Clamp: TPU Jaw Pads