Craftsman Narrow Spring Clamp Jaws

Quite some years ago I (ab)used several Craftsman (I’ve had them a long time) long narrow spring clamps while calibrating some thermocouples, much to the detriment of their rubbery jaws. The original gasket compound hackery didn’t work well, but eventually some of it stuck and I’ve been using them ever since:

Now that I can 3D print TPU, however, it was time to fit better jaws in those things.

The solid model eventually looked like this:

The OpenSCAD code is replete with juicy magic numbers based on what few measurements I could make, then tweaked to fit the jaw where it had to go:

<<< snippage >>>

NumPads = 2 * 4;

PadThick = 1.3;
TabHeight = 1.5;

module Tab() {

  difference() {
    linear_extrude(TabHeight)
      trapezoid(h=4.5,w1=1.4,w2=1.2,rounding=0.2,anchor=FRONT);
    back(5.5)
      xrot(60)
        cuboid([5,5,10],anchor=FRONT);
  }
}
<<< snippage >>>

if (Layout == "Build") {
nx = ceil(sqrt(NumPads));
ny = nx;

for (nx = [0:nx-1], ny = [0:ny-1])
  right(nx*Gap)
    back(ny*Gap)
      union() {
        linear_extrude(PadThick)
          trapezoid(h=7.5,w1=5.2,w2=4.2,rounding=0.2,anchor=FRONT);
        up(PadThick)
          back(0.5)
            Tab();
    }
}

The results is basically too small for the Prusa MK4 with the 0.8 mm nozzle laying down 0.4 mm layers, but the Makergear M2 with its 0.35 mm nozzle was in the midst of a heart attack at the time (about which, more later).

The PrusaSlicer preview shows the chunky result:

Because they’re so small, I printed nine at a time to get reasonable cooling and repair all four clamps.

A few iterations produced a workable size & shape:

The nicely curved profile comes from gluing them in place while gripping sturdy closed-cell foam:

I used E6000+ adhesive, mostly because the tube didn’t scamper out of the way, but classic E6000 with nasty solvents might be Even Better. Neither would bond to the clamp’s plastic, so the eventual repair will once again require prying out debris with a dental pick.

After resucitating the M2 , I resliced the model with 0.2 mm layers:

Which looks much prettier in real life:

A small ziplock bag with those nine pretty jaws now hangs from the rail supporting Too Many Clamps against future need.