The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Machine Shop

Mechanical widgetry

HQ Sixteen: Needle Bar Re-Reorientation
Unfortunately, orienting the HQ Sixteen’s Needle Bar to put the needle locking setscrew at the back resulted in excessive thread breakage:

HQ Sixteen – needle bar reoriented

The thread passes through the guide hole just below the hex driver in that photo, then through the hole in the needle from the front of the machine. Apparently the 45°-ish angle between those two was large enough to prevent the thread from sliding smoothly along the needle.

Proceeding much as before, but without dismantling the machine cover because I know where the clamp screw will be with the machine shaft at Bottom Dead Center …

The Ruler Foot is now 0.5 mm off the Needle Plate:

HQ Sixteen – Ruler foot clearance – 2

Stacking gauge blocks shows the Needle Bar now sits 0.355 inch above the Plate at BDC:

HQ Sixteen – gage block stack – 2

That is viewed from the right side of the machine, with the button-head screw sticking out of the Presser Bar hidden behind the Needle Bar.

The gauge block set confirming what’s in the stack:

HQ Sixteen – gage blocks used – 2

Then:
- Stick a screwdriver through the bottom access hole into the Needle Bar clamp screw
- Loosen the Needle Bar clamp screw
- Rotate the Needle Bar to put the guide hole exactly in front
- Tighten the clamp screw
- Verify the shaft is still at Bottom Dead Center
- Remove the block stack
- Install the Ruler Foot at 0.5 mm
Which looked like this with the shaft at Top Dead Center:

HQ Sixteen – needle bar reoriented – 2

There’s a quilt in progress on the left, so we’ll know if this solved the problem very shortly.
2026-09-15
Bike Rack Tray Holder: Small Version

Mary wanted to haul seedlings started in half-gallon milk bottles to their destination and I figured they shouldn’t slide around while being transported:

Milk bottle seedling starter carrier

That’s a half-width drawer from the same salvaged collection that produced the Bike Rack Tray Holder and a few minutes with LightBurn adapted the wider cardboard bike rack mount to fit the narrower drawer:

Bike Rack Tray Holder – small – LightBurn layout

Basically, use Node Edit to delete the horizontal lines, move the sides inward by half the difference of the drawer widths, then draw a few short lines to close the gaps.

Hot-melt gluing four layers of cardboard with crossed corrugations, plus three flat bottom layers, got it done:

Bike Rack Tray Holder – small drawer – installed

Those are the same stretchy TPU straps, with an additional link on each rear chain to compensate for the slightly higher block mount and a slightly narrower front block to fit in the slightly narrower drawer handle:

Bike Rack Tray Holder – half-width drawer straps

Of course, the only way to know what didn’t fit was to make a pair of the original ones, try them on for size, then adapt the OpenSCAD code accordingly.

That was surprisingly easy …

2026-09-09

PolyDryer Humidity: September

After six months to see how much moisture entered from the 50%RH (±5%RH) basement air:

	2026-09-07
Filament	%RH	Weight – g	Wt gain – g	Gain %
PETG White	26	56.2	6.2	12.4%	Gel
PETG Black	28	57.3	7.3	14.6%	Gel
PETG Orange	34	54.1	4.1	8.2%	Alumina
PETG Clear	37	54.4	4.4	8.8%	Alumina
PETG-CF Blue	38	54.0	4.0	8.0%	Alumina
PETG-CF Gray	34	56.4	6.4	12.8%	Gel
PETG-CF Black	25	56.3	6.3	12.6%	Gel
PETG Blue	38	55.9	5.9	11.8%	Alumina
TPU Clear	34	56.3	6.3	12.6%	Alumina
TPU Black	32	55.2	5.2	10.4%	Alumina

Sorted by relative humidity:

PETG-CF Black	25	56.3	6.3	12.6%	Gel
PETG White	26	56.2	6.2	12.4%	Gel
PETG Black	28	57.3	7.3	14.6%	Gel
TPU Black	32	55.2	5.2	10.4%	Alumina
PETG Orange	34	54.1	4.1	8.2%	Alumina
PETG-CF Gray	34	56.4	6.4	12.8%	Gel
TPU Clear	34	56.3	6.3	12.6%	Alumina
PETG Clear	37	54.4	4.4	8.8%	Alumina
PETG-CF Blue	38	54.0	4.0	8.0%	Alumina
PETG Blue	38	55.9	5.9	11.8%	Alumina

Fairly obviously, there is no correlation between the humidity level and the amount of adsorbed water.

The silica gel beads were rather dark, not that that means much:

Silica Gel beads - 2026-09-07 — Silica Gel beads – 2026-09-07

All the boxes now contain 50 g of alumina beads.

2026-09-08

Nasal Strip Cushion

Having a mild allergy to whatever plant pollen has begun drifting around these days, I’m trying cheap “nasal strips” intended to hold my nose open overnight, which seem less awful than any of the variety of decongestant / allergy relief pills or potions.

However, while the strips have an adhesive layer strong enough to stick overnight to a slightly oily nose, the skin on the bridge of my nose is fragile enough to hurt after peeling the strip off in the morning. As I see it, the strips need adhesive only on their ends, where they pull outward on my nose, because the center part pushes inward on the bridge.

A few minutes with a rotary cutter and scrap fabric produced dozens of small cushions:

Nasal Strip cushion

Quite inadvertently, the blue fabric looks downright medical.

Your mileage will vary, but the exposed adhesive on the ends sticks firmly to the sides of my nose and, with the cloth protecting the bridge, the strip peels off without injury.

Despite converting other scrap fabric into shop wipes, these tiny cushions are unsuited for laser cuttery, as waking up in the middle of the night with even the faintest campfire smell in my nose would be … triggering.

2026-09-07
Freezer Tray Rack

The new chest freezer’s interior has a rectangular lump on the right side over the compressor, atop which we’d been stacking foam trays of ground meat. To forestall a tragic landslide, I made a quick-n-easy rack held together with hot-melt glue:

Freezer Tray Rack – test fit

It doesn’t look like it grew there, but it’ll suffice:

Freezer Tray Rack – installed

The weird black things are silicone molds for 4 fl. oz. ice balls (known in these parts as “iceteroids”) suited for chilling the water used to quench veggies after steaming / blanching, prior to freezing.

The LightBurn layout arranges the parts in tool-layer rectangles matching a shipping box of 6.5 mm cardboard rugged enough for at least a prototype:

Freezer Tray Rack – LightBurn layout

The jawbreaker boxes.py URL adds 5 mm to the shelf height for a little more clearance. You’ll likely have different cardboard in your stockpile, so tweak as needed, add vent holes in the sides & back, and Fire The Laser.

2026-09-03
Smashed Glass Coasters: Chipboard Variation
The summer season brings iced drinks with condensation trickling down the mug and, alas, running off the smashed glass coasters:

Printed Coaster – Set C – oblique

The hard parts of making those coasters involved converting the glass fragment outlines into vectors and arranging them in interesting patterns. However, with those files already in hand, making a similar coaster with chipboard “fragments” was straightforward:

Chipboard Fragment Coaster – detail

Slightly modify the OpenSCAD code to suit thinner chipboard:
```
include <BOSL2/std.scad>

fn = "Printed Fragment Coaster - 5 in Set B - Inkscape paths.svg";

FragmentThick = 0.8;

BaseThick = 2.0;
RimHeight = 0.4;

union() {


  linear_extrude(h=BaseThick)
    import(fn,id="Perimeter");

  color("Green")
    up(BaseThick)
      linear_extrude(h=FragmentThick)
        difference() {
          import(fn,id="Perimeter");
          import(fn,id="Recesses");
        }

  color("Red")
    up(BaseThick + FragmentThick)
    linear_extrude(h=RimHeight)
      difference() {
        import(fn,id="LipOut");
        import(fn,id="LipIn");
        import(fn,id="Island");
      }

}
```
Run the solid model through PrusaSlicer:

Chipboard Fragment Coaster B – slicer preview

And have a baseplate an hour later:

Coaster Printing – in progress

While that’s buzzing away, tell LightBurn to cut chipboard instead of metallized paper, stick some craft adhesive sheet on the chipboard, and Fire The Laser:

Chipboard Fragment Coaster – chipboard cutting

Remember to mirror the fragments, because you’re cutting them bottom-up.

Do the same for the cork sheet going on the bottom, which does not require mirroring.

I tossed the cardboard alignment fixtures I used to stick the cork onto the 3D printed baseplate, so make another one for each coaster.

The top layer holds the baseplate:

Chipboard Fragment Coaster – cork fixture – top

The cork + adhesive sheet is inset 0.5 mm from the edge of the baseplate, so the outline cut in the bottom layer of cardboard is just that much smaller:

Chipboard Fragment Coaster – cork fixture – bottom

Although the time used to make a fixture isn’t deducted from your allotment, I’m not sure about making two identical fixtures, so I’m saving these for the next time.

Then peel-n-stick the chipboard fragments in their recesses:

Chipboard Fragment Coaster – variety

The first baseplate didn’t have raised rims around the fragments (because there’s no need to retain any epoxy), but the result looked kinda … flat:

Chipboard Fragment Coaster – flat top

Fixing that was a matter of not setting the rim height to zero in the OpenSCAD code.

It’s perfectly functional even without a rim:

Printed Coaster – chipboard inserts – sweaty mug

Protip: White chipboard is a Terrible Idea™ in a quick-n-easy laser cuttery project. All the rest have only red or blue fragments for a good reason.

Conversely, white PETG makes a nice contrast to the deep red and blue.

Prosit!
2026-08-28
Bike Helmet Mirror: Always Have A Spare

As fate would have it, the telescoping stalk on Mary’s helmet mirror broke off at the ball mount a few days after I assembled another spare mirror:

Helmet Mirror Ball Mount – broken shaft

That’s the point where all the stress concentrates, but the stalk lasted almost exactly six years and didn’t owe me anything.

So I clamped the mirror+shaft+ball from a spare into the mount on her helmet, and she rode off as planned.

Once again being down to a single spare, I drilled a few more 10 mm balls:

Helmet Mirror Ball Mount – ball drilling

Cleaning up the end of the broken shaft let me shove it into a drilled ball:

Helmet Mirror Ball Mount – repaired – drilled balls

The insert and random screw came from the stub end of the broken shaft: ramming it into the cleaned-up end makes the job look Good Enough™.

Clamp the repaired stalk into the spare mount, drop the drilled balls & lathe fixture back in their bag, and maybe it’ll be another six years before they’re needed.

Life is good!

2026-08-25