Machine Shop – Page 14 – The Smell of Molten Projects in the Morning

WS-5000 Anemometer Bird Spike Ring

A critter made off with our battered plastic rain gauge, so I set up an Ambient Weather WS-5000 station to tell Mary how much rain her garden was getting. I added the Official Bird Spike Ring around the rain gauge to keep birds off, but robins began perching atop the anemometer while surveying the yard and crapping on the insolation photocell.

After a few false starts, the anemometer now has its own spikes:

It’s a snugly fitting TPU ring:

Weather Station Spikes - build test piece — Weather Station Spikes – build test piece

The spikes are Chromel A themocouple wire, because a spool of the stuff didn’t scamper out of the way when I opened the Big Box o’ Specialty Wire. As you can tell from the picture, it’s very stiff (which is good for spikes) and hard to straighten (which is bad for looking cool).

The shape in the middle is a hole diameter test piece. Next time around, I’ll use thicker 14 AWG copper wire:

Weather station spikes - test piece — Weather station spikes – test piece

The test piece showed I lack good control over the TPU extrusion parameters on the Makergear M2, as holes smaller than about 2 mm vanish, even though the block’s outside dimensions are spot on. This application wasn’t too critical, so I sharpened the wire ends and stabbed them into the middle of the perimeter threads encircling the hole.

Now we’ll discover how TPU survives weather.

The OpenSCAD source code as a GitHub Gist:

	// Ambient Weather – Ambient Weather WS-5000 anemometer bird spike ring
	// Ed Nisley – KE4ZNU
	// 2025-06-09

	include <BOSL2/std.scad>

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

	/* [Hidden] */

	HoleWindage = 0.2;
	Protrusion = 0.1;

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

	SpikeOC = 30.0; // straight-line distance between spikes, OEM = 35

	WallThick = 4.0;

	BandID = 3.5*INCH – 0.5; // = OD of weather station
	BandOD = BandID + 2*WallThick;

	BandHeight = 8.0;

	SpikeOD = 1.7 + HoleWindage; // wire diameter
	SpikeWall = 2.0; // around wires

	SpikeBCD = BandOD;

	MountOD = SpikeOD + 2*SpikeWall;

	NumSpikes = ceil(PI*BandOD/SpikeOC); // need integral number of spikes
	SpikeAngle = 360/NumSpikes;
	NumSides = 3*NumSpikes;

	echo(SpikeAngle=SpikeAngle);
	echo(NumSpikes=NumSpikes);


	//———-
	// Define Shapes

	module Slice() {

	difference() {
	hull() {
	pie_slice(h=BandHeight,d=BandOD,$fn=NumSides,ang=SpikeAngle,spin=-SpikeAngle/2,anchor=BOTTOM);
	right(SpikeBCD/2 – MountOD/2)
	cyl(h=BandHeight,d=MountOD,realign=true,anchor=LEFT+BOTTOM,$fn=2*6);
	}
	down(Protrusion) {
	cyl(h=BandHeight + 2*Protrusion,d=BandID,$fn=NumSides,circum=true,realign=true,anchor=BOTTOM);
	right(SpikeBCD/2)
	cyl(h=BandHeight + 2*Protrusion,d=SpikeOD,$fn=6,circum=true,realign=true,anchor=BOTTOM);
	}
	}

	}

	module SpikeRing() {

	for (i=[0:NumSpikes-1])
	zrot(i*SpikeAngle)
	Slice();


	}

	//———-
	// Build things

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


	if (Layout == "Show") {
	left(SpikeBCD/2)
	Slice();
	SpikeRing();
	}

	if (Layout == "Build") {
	SpikeRing();
	}

view raw Weather Station Spikes.scad hosted with ❤ by GitHub

2025-06-12

PolyDryer Internal Fan Puzzle

With the humidity inside the PolyDryer boxes being roughly proportional to the amount of filament on the spool, I printed a slightly modified airlock plate and a TPU seal ring, then stuck a tiny fan on it:

PolyDryer airlock plate - tiny fan — PolyDryer airlock plate – tiny fan

It just barely clears the curved air guide inside:

PolyDryer airlock plate - tiny fan installed — PolyDryer airlock plate – tiny fan installed

The tea bags full of desiccant allow some wind between them and the filament in the spool, but I obviously must re-think that setup. There’s enough clearance for what should be reasonable circulation, so i defined it to be good enough for now.

The box of TPU started at 25 %RH, dropped to 22 %RH overnight, then returned to 25 %RH the next day:

PolyDryer TPU - 25 pct RH — PolyDryer TPU – 25 pct RH

Now that I’m watching more often, I’ve seen the meter glitch to 10% for a few seconds:

PolyDryer TPU - 10 pct RH glitch — PolyDryer TPU – 10 pct RH glitch

A humidity indicator card suggests the air is under 20 %RH:

PolyDryer TPU - humidity indicator card — PolyDryer TPU – humidity indicator card

It may be the filament can outgas water vapor as rapidly as the desiccant can remove it, but I expected the fan to make at least a little difference.

I have no idea what’s going on in those boxes.

2025-06-10

Screen Door Handle Repositioning

For unknown reasons, the handle on the porch screen door was installed less than one finger width from the frame, so I conjured a pair of plastic plates shifting it far enough to prevent finger pinches and avoid the screws for the outside handle:

The original holes now have M4 threaded wood inserts and the holes in the ¼ inch acrylic have M4 heat-staked brass inserts, mostly because I had everything on hand.

This was part of a project to trim the bottom of the door to clear the porch floor boards, which evidently continued warping after they trimmed the door to fit:

That thin blue line suggests the highest part of the floor was once near the bottom of the picture, but it’s now the lowest part. The highest part is now near the hinge side near the top of the picture, firmly jamming the door in place.

Works great now!

2025-06-09

Pepper Mill: End of Life

So I finally took our pepper mill apart to see why it was having trouble grinding peppercorns:

It was a wedding present and, nigh onto half a century later, it’s all worn out.

Its replacement surely won’t survive so long, even with ceramic innards, but I may not notice.

2025-06-05

Shower Head Hose Clamp

The new shower head’s hose dangled directly in front of the faucet knob, so I conjured a simple clamp to pull the down-going half over to the side of the stall and keep the up-going half away from the faucet:

The black nylon M6 screw goes into a hole tapped in the plastic cap atop the aluminum extrusion; I was mildly surprised that worked as well as I hoped. It’s basically invisible from outside the shower stall.

Stipulated: laser-cut 3 mm acrylic probably isn’t the right material for the job, but it’s a quick & easy way to discover if that’s the right place to clamp the hose.

While installing those two pieces, it occurred to me the result would be much stronger if the two “jaws” overlapped and had a pair of screws holding them together, so the LightBurn layout includes that idea for the next time:

Shower Head Hose Clamp - LightBurn layout — Shower Head Hose Clamp – LightBurn layout

The Hole Template simplified getting the hole dead center in the plastic cap, because drilling it required an awkward reach across the end of the vanity.

There is zero chance this will fit your shower & hose, but now you have the general idea.

2025-06-03

PolyDryer Humidity vs. Spool Fill

The Basement Shop has 50±5% relative humidity, with the top held down by a hulking dehumidifier (plus a box fan stirring the air) and the bottom supported by being a basement. As a result, the 3D printer filament stabilized at about 50% RH, which seemed to work well enough for PETG.

Adding TPU to the stable called for better humidity control, so I set up a bunch of PolyMaker PolyDryer boxes with Auto-rewind spindles.

After a few weeks, though, I didn’t expect this:

That’s activated alumina desiccant, mostly because it’s reputed to have more capacity and a lower ultimate humidity than silica gel, but it likely doesn’t make much difference.

In addition to 25 g of desiccant in the PolyDryer meter case, I dropped five teabags holding 10 g each in the bottom of the box for more capacity. I measure the desiccant by putting 75.0 g into a cup, putting 25.0 g in the PolyDryer meter box (aided by a Polydryer Desiccant Funnel), 10.0 g into four teabags, and whatever’s left into the fifth teabag, thus eliminating rounding errors in the smaller quantities.

The stabilized humidity inside the boxes seems to depend on the amount of filament on the spool:

Nearly full → 25% to 30% RH
Half full → 20%-ish RH
Nearly empty → 10% to 15% RH

I think the humidity level comes from the filament outgassing water vapor through its (limited) surface area on the outer layer around the spool. The difference between that rate and the desiccant’s ability to remove water vapor from the (unmoving) air in the box sets the stable humidity: more surface area → more water vapor → higher humidity.

After the filament eventually dries out, the humidity should decrease, but diffusion is a slow process. More likely, the humidity will remain stable as the printer pulls filament from the outer layer and exposes the somewhat wetter plastic within.

The heater and fan inside the PolyDryer base unit circulates hot air through the box around the spool, but depends on the desiccant to remove water vapor. Running the base unit for 6 or 12 hours makes little difference in the stabilized humidity, so I think the desiccant is doing the best it can as the filament outgasses more water vapor.

Using Air Exchanger vents seems to make no difference, likely because the desiccant must then pull more water vapor out of the incoming 50% RH basement air. A psychrometric chart says 50% RH air at 60 °F becomes 10% RH air at 120 °F, but moisture in the filament wrapped around the spool can’t escape any faster.

So, for example, a full spool of TPU starting at 25% RH:

PolyDryer humidity - TPU start — PolyDryer humidity – TPU start

Six hours of drying pulls it down to 22%:

PolyDryer humidity - TPU finish — PolyDryer humidity – TPU finish

After sitting overnight it’s back at 25%:

PolyDryer humidity - TPU after 14 hr — PolyDryer humidity – TPU after 14 hr

Admittedly, that was with the vents in place, but the closed box started at 25% RH after sitting around for a week or so following a similar drying cycle.

The desiccant had absorbed 4 g of water since I put it in, so it hasn’t been entirely idle.

Which suggests 75 g of activated alumina desiccant is workin’ hard and doin’ swell in there, with the filament acting as an essentially infinite reservoir of water vapor.

I haven’t noticed any particular difference in PETG print quality and the TPU hasn’t gotten enough mileage to notice much trouble, but reducing the MMU3 buffer clutter was totally worth the effort.

2025-06-02

HQ Sixteen: Nose Ring Lights

We don’t know what the proper term might be for this part of the machine, but it looks sorta like a nose and the lights form most of a ring around it, so I’m going with “Nose Ring Lights”:

The general idea is to put more light on the quilt than the Chin Light, which looked pretty good until the COB LED strip started flickering as the LEDs failed.

Handi-Quilter sells a ring light for machines manufactured a decade later than ours, but it uses a built-in USB jack this machine lacks.

One of two (apparently) unused M4 holes on the left side of the machine frame suggested a mounting point for a 3D printed bracket:

HQ Sixteen Nose Ring Lights - solid model — HQ Sixteen Nose Ring Lights – solid model

The ramp matches the 3° (-ish) mold draft of the machine frame, which I initially ignored by angling the tab, but a tilted frame looked awful; it’s now aligned with local horizontal..

A few iterations got all the pieces & holes in their proper places:

HQ Sixteen Nose Ring lights - iterations — HQ Sixteen Nose Ring lights – iterations

The smaller (rampless) bracket has three LED strips, but a quick test showed more light would be better:

HQ Sixteen Nose Ring lights - bottom view — HQ Sixteen Nose Ring lights – bottom view

The lack of a transparent-ish cover is obviously unsuitable for a commercial product, but the key design goal is to not interfere with spreading as much light as possible across as much of the quilt as possible. The black JB Weld Plastic Bonder blobs keep the 24 VDC supply out of harm’s way, which is as good as it needs to be for now.

The bracket has three sides, because the right side of the machine has all the thread guide hardware. Putting anything over there seemed likely to interfere with either thread movement or fingers making adjustments.

Fortunately, the wider bracket doesn’t stick out too far beyond the machine frame and the doubled LED strips create a much smoother light pool:

HQ Sixteen Nose Ring lights - left front view — HQ Sixteen Nose Ring lights – left front view

Yes, the quilt is focused and the LED frame is blurred.

The larger light-emitting area reduces the shadow under the left rod (supporting the ruler foot) enough to be unobjectionable.

A 0.2 mm layer thickness transforms the smooth ramp into stair steps:

HQ Sixteen Nose Ring Lights - PrusaSlicer — HQ Sixteen Nose Ring Lights – PrusaSlicer

They’re inconspicuous after the bracket is installed.

The Chin Light ran on 12 V and these strips require 24 V, so the OpenSCAD code creates a pair of endcaps for the new supply, which is of course completely different than the old supply. Setting that up must await quilt completion.

The OpenSCAD source code as a GitHub Gist:

	// HQ Sixteen Nose Ring Lights
	// Ed Nisley – KE4ZNU
	// 2025-05-23

	include <BOSL2/std.scad>

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

	// Number of side-by-side LED strips
	Strips = 2;

	/* [Hidden] */

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

	$fn=NumSides;

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

	Gap = 5.0;

	WallThick = 5.0; // default thickness for things

	NoseRadius = 6.0; // corner roundoff

	NoseOA = [44.0,36.5]; // overall nose size
	NoseAngles = [87,87]; // front & rear inward angles wrt left side

	NoseCenters = [ // centers of circles defining the nose corners
	[NoseRadius, NoseOA.y/2 – NoseRadius],
	[NoseRadius,-(NoseOA.y/2 – NoseRadius)],
	[NoseOA.x – NoseRadius, NoseOA.y/2 – NoseRadius – (NoseOA.x – 2NoseRadius)tan(90 – NoseAngles[0])],
	[NoseOA.x – NoseRadius,-(NoseOA.y/2 – NoseRadius – (NoseOA.x – 2NoseRadius)tan(90 – NoseAngles[1]))],
	];

	LEDMargin = 1.0;
	LEDStrip = [41.5 + LEDMargin,8.0 + LEDMargin,1.8 + 0.2]; // 24 V COB LED strip unit + windage
	LEDBaseOA = [LEDStrip.x + StripsLEDStrip.y,NoseOA.y + 2Strips*LEDStrip.y,WallThick]; // LED mount

	DraftAngle = 3.0; // angle of frame wrt horizontal at right end of nose
	DraftWedge = [NoseOA.x,NoseOA.y + 2LEDStrip.y,NoseOA.xtan(DraftAngle)];

	HoleOffset = [-10.0,5.5,DraftWedge.z + 10.0]; // from left front corner of nose
	HolePosition = HoleOffset + [0,-NoseOA.y/2,WallThick]; // absolute coordinates from origin

	Screw = [4.0 + HoleWindage,9.0,2.0]; // LENGTH=button head

	Bracket = [WallThick,Screw[OD] + 4.0,HoleOffset.z + Screw[OD/2] + 2.0 + WallThick];

	Supply = [46.0,30.0,21.0]; // 24 VDC power supply
	SupplyScrewOffset = 5.0; // … M4 screw hole from end of supply case

	CapWall = 3.0;
	CapRadius = CapWall – 1.0;
	CapInset = 1.0;
	CapOA = [20.0,Supply.y + 2*CapWall,Supply.z + CapWall]; // x & y to cover existing holes

	//———-
	// Define Shapes

	//—– 2D outline of nose piece just under frame casting

	module NosePlan() {
	hull()
	for (p = NoseCenters)
	translate(p) circle(r=NoseRadius);
	}

	//—– LED mounting plate

	module Mount() {

	union() {
	difference() {
	union() {
	right(LEDBaseOA.x/2 – Strips*LEDStrip.y)
	cuboid(LEDBaseOA,rounding=WallThick/2,except=BOTTOM,anchor=BOTTOM);
	up(LEDBaseOA.z) left(-HoleOffset.x/2)
	yrot(DraftAngle)
	cuboid(DraftWedge,rounding=WallThick/2,edges="Z",anchor=LEFT+BOTTOM);
	}
	down(Protrusion)
	linear_extrude(LEDBaseOA.z + DraftWedge.z + Protrusion)
	NosePlan();
	if (Strips > 1)
	translate([HolePosition.x – Bracket.x/2,HolePosition.y – Bracket.y,-Protrusion])
	cyl(LEDBaseOA.z + 2*Protrusion,d=4.0,anchor=BOTTOM);
	}
	difference() {
	union() {
	translate([HolePosition.x,HolePosition.y,(Bracket.x/2)*sin(DraftAngle)])
	left(Bracket.x)
	cuboid(Bracket,rounding=WallThick/2,edges=LEFT,anchor=BOTTOM+LEFT);
	translate([HolePosition.x – Bracket.x/2,HolePosition.y,0]) // rounding filler
	cuboid([LEDStrip.y,Bracket.y,WallThick],anchor=BOTTOM+LEFT);
	}
	translate(HolePosition)
	xrot(180/6) xcyl(l=NoseOA.x,d=Screw[ID],$fn=6);
	}
	}
	}

	//—– Endcap for power supply

	module EndCap() {

	difference() {
	cuboid(CapOA,rounding=CapRadius,except=BOTTOM,anchor=LEFT+BOTTOM);
	right(CapOA.x – CapWall) down(Protrusion)
	cuboid(Supply + [0,0,Protrusion],anchor=RIGHT+BOTTOM);
	right(CapInset + SupplyScrewOffset)
	zcyl(l=2*CapOA.z,d=Screw[ID],$fn=6,anchor=BOTTOM);
	}

	}


	//———-
	// Build things

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

	if (Layout == "PowerCap") {
	EndCap();
	}

	if (Layout == "Show") {
	Mount();

	ctr = 80;
	ofs = Supply.x/2 – CapInset;
	left(ctr – ofs)
	EndCap();
	left(ctr + ofs)
	xflip()
	EndCap();
	color("Silver",0.6)
	left (ctr)
	cuboid(Supply,anchor=BOTTOM);
	}

	if (Layout == "Build") {
	Mount();
	back((LEDBaseOA.y + CapOA.y)/2 + Gap) right(Gap) up(CapOA.z) zflip()
	EndCap();
	back((LEDBaseOA.y + CapOA.y)/2 + Gap) left(Gap) zrot(180) up(CapOA.z) zflip()
	EndCap();
	}

view raw HQ Sixteen Nose Ring Lights.scad hosted with ❤ by GitHub

2025-05-30