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.
Given the cracking caused by vector patterns on CDs and DVDs, seeing stress cracks open up on large-area engravings came as no surprise:
They start smaller in the more closely engraved areas:
But eventually spread over the entire surface:
They’re not always straight:
And aren’t aligned with the engraving path:
My threat model says those discs are definitely unreadable …
For whatever reason, the Thunar file browser in XFCE does not automagically show thumbnails for webp images. Some searching produced a recipe, although the displayed webp.xml file needs the last two lines to close the tags:
<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
<mime-type type="image/webp">
<comment>WebP file</comment>
<icon name="image"/>
<glob-deleteall/>
<glob pattern="*.webp"/>
</mime-type>
</mime-info>
The magic copy-to-clipboard button includes those tags, so I suppose it’s another case of being careful what you believe on the Intertubes.
Going through the steps displayed images of the Subpixel Zoo:
They’ll turn into layered paper patterns:
After installing (if that’s not too fancy a term) the horizontal thread spool adapter on the HQ Sixteen, I laser-cut an acrylic disk to keep thread cones centered on the other vertical spool pin:
It’s trivial: an 11 mm circle to clear the washer and a 55 mm circle to locate the cone.
However, I cut that disk with a 56 mm OD, because that’s what I measured on half a dozen cones. Come to find out at least some cone bases are juuust slightly oval and they latched onto that disk like they were gonna be best buddies forever.
Rather than cut another acrylic disk, I laser-cut a friction ring from a scrap of stamp-pad rubber and jammed the disk against the chuck with a live center:
A few minutes of sissy cuts made the disk nicely round and concentric with the inner hole, with a little file work knocking the edges off the rim.
Done!
Along with the Beelink PC, putting the Anker USB hub on the monitor mount pole helped tidy the cables just a little bit:
It’s still jumbled, but at least the cables aren’t wagging the hub.
This clamp needs only one M6 screw into a square nut:
Again better seen in cross-section:
The OpenSCAD code extrudes the shape from a 2D arrangement, then punches the screw through the side:
// Monitor Pole box clamp
// Ed Nisley - KE4ZNU
// 2025-01-23
include <BOSL2/std.scad>
/* [Hidden] */
ID = 0;
OD = 1;
LENGTH = 2;
Protrusion = 0.1;
Box = [22.5,45.5,25.0]; // Z is clamp height
BoxGrip = 5.0; // on outer side clearing connectors
PoleOD = 30.5;
WallThick = 5.0;
Kerf = 3.0; // clamping space
Clearance = 2*0.2; // space around objects
Washer = [6.0,12.0,1.5]; // M6 washer
Nut = [6.0,10.0,5.0]; // M6 square nut
MidSpace = 35.0; // pole to box spacing
ClampOAL = Box.x + MidSpace + PoleOD + 2*WallThick;
//----------
// Build it
difference() {
linear_extrude(height=Box.z,convexity=5)
difference() {
hull() {
right(MidSpace/2 + Box.x/2)
rect(Box + 2*[WallThick,WallThick],rounding=WallThick);
left(MidSpace/2 + PoleOD/2)
circle(d=PoleOD + 2*WallThick);
}
right(MidSpace/2 + Box.x/2)
square(Box + [Clearance,Clearance],center=true);
right(MidSpace/2 + Box.x)
square([Box.x,Box.y - 2*BoxGrip],center=true);
left(MidSpace/2 + PoleOD/2)
circle(d=PoleOD + Clearance);
square([2*ClampOAL,Kerf],center=true);
}
up(Box.z/2) {
xrot(90)
cylinder(d=Washer[ID] + Clearance,h=2*Box.y,center=true,$fn=6);
fwd(Box.y/2 - Washer[LENGTH])
xrot(90) zrot(180/12)
cylinder(d=Washer[OD] + Clearance,h=Box.y,center=false,$fn=12);
back(Box.y/2 + Nut[LENGTH]/2)
xrot(90)
cube([Nut[OD],Nut[OD],2*Nut[LENGTH]],center=true);
}
}
The alert reader will have noticed I didn’t peel the protective film off the hub, which tells you how fresh this whole lashup is.
Clearing the clutter off the top of the laser put the monitors up on mounts clamped to its wings, which required an adapter between the monitor and the mount’s standard VESA bracket:
The Beelink PC has an adapter plate intended to put it on that VESA bracket, too, but a quick test showed the power button pointed downward in an inaccessible spot. I eventually realized the Beelink would fit neatly on the monitor mount’s pole:
The view from the other side:
The clamps have recesses for an M6 square nut and an M4 brass insert:
Which is better seen in a cross-section:
The M6 screw uses the same hex wrench as the rest of the monitor mount and the M4 screw fits the VESA bracket. Sometimes, you just gotta go with the flow.
Pondering those pictures will show why the nut and insert must be on opposite sides. I came that close to building one to throw away.
The OpenSCAD source code extrudes the overall shape upward, then punches the screw holes & fittings horizontally:
// Monitor Pole Beelink clamp
// Ed Nisley - KE4ZNU
// 2025-01-23
include <BOSL2/std.scad>
/* [Hidden] */
ID = 0;
OD = 1;
LENGTH = 2;
Protrusion = 0.1;
PoleOD = 30.3;
WallThick = 5.0;
Kerf = 3.0; // clamping space
Clearance = 2*0.2; // space around objects
Screw = [6.0,10.0,6.0]; // M6 SHCS, LENGTH = head
Washer = [6.0,12.0,1.5]; // M6 washer
Nut = [6.0,10.0,5.0]; // M6 square nut
Insert = [4.0,5.8,10.0]; // M4 insert
ScrewSpace = Washer[OD]; // pole edge to screw center spacing
Block = [4*ScrewSpace + PoleOD + 2*WallThick,PoleOD + 2*WallThick,2*Washer[OD]]; // Z = clamp thickness
//----------
// Build it
difference() {
linear_extrude(height=Block.z,convexity=5)
difference() {
rect([Block.x,Block.y],rounding=WallThick);
circle(d=PoleOD + Clearance);
square([2*Block.x,Kerf],center=true);
}
up(Block.z/2) {
right(PoleOD/2 + ScrewSpace){
xrot(90)
cylinder(d=Washer[ID] + Clearance,h=2*Block.y,center=true,$fn=6);
fwd(Block.y/2 - Washer[LENGTH])
xrot(90) zrot(180/12)
cylinder(d=Washer[OD] + Clearance,h=Block.y,center=false,$fn=12);
back(Block.y/2)
xrot(90)
cube([Nut[OD],Nut[OD],2*Nut[LENGTH]],center=true);
}
left(PoleOD/2 + ScrewSpace) {
xrot(-90)
cylinder(d=Insert[ID] + Clearance,h=2*Block.y,center=true,$fn=6);
fwd(Block.y/2 - 1.25*Insert[LENGTH])
xrot(90)
cylinder(d=Insert[OD] + Clearance,h=Block.y,center=false,$fn=6);
}
}
}
It’s done in PETG-CF, which looks surprisingly good in a chonky sort of way. I’ll find out how well it withstands moderate clamping forces.
Although we had considerable success trapping voles during the last half of the 2024 gardening season, Mary found a description of what might be a better technique: a box with small entrance holes taking advantage of rodent thigmotaxis: their tendency to follow walls. The writeup shows nicely made wood boxes, but I no longer have machinery capable of cutting arbitrarily large wood slabs into pieces.
I do, however, have a vast pile of cardboard boxes:
That’s a rat-size trap.
A smaller box has room for two mouse-size traps (one hidden on the left):
The general idea: plunk the box in a garden plot, arm the trap(s), close the lid, and eventually a vole will venture inside, whereupon wall-following leads to disaster. Apparently bait is optional, as wall-following inevitably takes them over the trap pedal. I won’t begrudge them a walnut or two, should bait become necessary.
Cardboard is obviously the wrong material for a box in an outdoor garden, but I figure they’ll survive long enough to show feasibility and I can deploy a lot of small boxes before having to conjure something more durable.
Yes, those are laser-cut rounded-rectangle holes: 30 mm and 40 mm, assuming voles care about such things.
Edit: More on voles.
A LightBurn video suggested large scan line intervals for decorative effects, so I adapted the SCP warning labels to fit 4 inch CD/DVD discs, set up the fixture, and Fired The Laser:
The overall effect is, in most lighting, subtle:
The pair on the right with inverted engraving areas are bolder:
From a distance these two look similar, but a line interval of 0.50 mm (on the left) produces a distinct lined effect compared to the overall frosty look for 0.25 mm (open in a new tab & zoom in):
The left and right edges of the disc warp upward as the surface melts and cools, pulling the disc into a potato chip shape. Doing large areas with 0.5 mm spacing produces less warp than 0.25 mm.
The laser barely fires at 10% power (on the right) and produces a line with a distinct granular look compared the smoother result at 20% (on the left), both at 0.50 mm interval to show the lines:
A 2 mm border at 0.25 mm interval (on the right, with a DVD) appears lighter than the central area at 0.50 mm (the CD on the left does not have the border):
A closer look at the border:
The reason behind the granular effect at 10% power is more obvious with higher magnification:
The spots off to the right are surface imperfections and dirt, not random laser tube firing.
The border and the central area happen on two different passes, so it’s comforting to see how closely the scan lines match.
I glued pairs of discs together with E6000 adhesive to discover whether it’s less awful than cutting and aligning adhesive sheets. Yup, much better, but white adhesive requires better path control to keep it out of the transparent ring around the hub and better quantity control to prevent blobs from squooshing out around the perimeter. Using clear adhesive would help, as would a fresh tube without a plug of cured gunk blocking the nozzle.
Once again, I have Too Many Coasters.
The Smell of Molten Projects in the Morning 