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

Samsung Range Grate Feet

The Samsung range has ungainly cast-iron (or some such) grates that have long since worn out / lost their original Genuine Samsung rubber bumper feet. The grates had glued-on feet that looked very much like they belonged under something else, affixed with mystery adhesive that stuck firmly in some corners and let go in others:

Samsung grate – old foot

It seems Samsung no longer sells replacement feet, which may be an indication they don’t want customer complaints, so I got a bag of nominally compatible rubber feet from the usual source and broke out the cyanoacrylate glue:

Samsung grate – new foot

The red flecks are traces of a previous generation of adhesive, with the new cyanoacrylate peeking out around the base of the new foot.

The grates have holes for the stems of the feet, so in principle they have plenty of resistance to being shoved around. In practice, tipping the grates up to clean underneath them dislodged the feet with depressing regularity. The grates are too heavy and too awkward to remove and plunk somewhere else, which suggests this sort of range is better suited to a kitchen that’s never used or, perhaps, comes equipped with a support staff.

You’re supposed to use high-temperature adhesive and, in fact, the red flecks look remarkably like high-temp silicone gasket compound, but all the missing feet were along the back of the grates where the small & simmer burners live, so I figured cyanoacrylate was certainly worth a try.

When & if they fall out, I’ll know when they went in.

2024-07-18
Laser Test Paper Beam Alignment Targets

Having failed at making flexible plant tags, I figured using laser test paper to make laser test targets might work:

Test paper – target patterns – 2024-07-03

They descend from my original dot-mode laser beam targets:

OMTech 60W laser – beam alignment – 2022-03-22

The dots just barely punch through the back side (open in a new tab & zoom for more dots):

Test paper – target patterns back side- 2024-07-03

The plastic coating chars and buckles with each pulse, but remains in place:

Test paper – 2 shot – uncleaned – 2024-07-03

Wiping the surface removes the loose coating / ash / debris to expose the underlying charred paper core:

Test paper – 2 shot – wiped – 2024-07-03

Those are two pulses marking the ends of each axis, so the machine remains well aligned after the fourth-quarter tweak.

A single pulse shows the beam has a nice round shape with well-defined edges:

Test paper – 1 shot – wiped – 2024-07-03

In principle, the beam should be more intense toward the middle, but I suspect that’s beyond the paper’s ability to resolve the energy; the beam either burns through the coating or it doesn’t. In all those targets, the back surface of the paper remains undamaged.

Manila paper targets seem to have better energy resolution and take much less time to produce:

Beam Alignment – Mirror 2 detail – 2023-09-16

The black test paper will certainly come in handy for something, though.

2024-07-17
Door Knob Lock Orientation

For the usual historic reasons, the exterior doors on our house all have different knobs with different lock orientations (and keys), so it’s difficult (for me, anyway) to verify they’re locked with just a glance. The correct solution of replacing all the knobs seems like a great deal of effort & expense for very little benefit.

This is easier, albeit considerably less stylish:

Doorknob 1

When the twisty thing aligns with the label, it’s locked:

Doorknob 3

No matter what orientation it has:

Doorknob 2

The scars in the paint show some of those doors have sported many knobs over the last half century or so.

You’d think such a thing could be standardized, but nope.

If we lived in a fancier house, I probably couldn’t get away with it.

2024-07-11
Clothes Washer Hose Bumpers

For obvious reasons, the water hoses tend to thump against the wall and the sheet-metal back of the clothes washer, so I added foam disks to mute the noise:

Clothes washer hose bumpers

They’re closed-cell polyethylene foam, laser-cut from a sheet about 15 mm thick. The cut is a yawning 2 mm wide near the top, but it pretty much doesn’t matter in this application.

The black line in the split is a snippet of the usual outdoor-rated foam tape, which probably won’t stick well to PE foam. If these fall apart, a cable tie around their waist should suffice.

The nice clip in the foreground is one of two intended to corral the drain hose. It’d be nice if LG included a few clips for the water hoses, but no matter where they were, the hoses would want to go elsewhere.

2024-07-10
Acrylic Grid Bathtub Soap Tray

Although the house has a shower stall, I want to fix the cracks in its floor before we use it, so we’ve been taking showers in one of the bathtubs. As is always the case, the soap tray / grab handle is positioned for someone reclining in the tub, making it both too low and too awkward for either of us.

Normally, I’d just stick a soap tray on the wall and be done with it, but the tub wall is covered with small tiles that defeat sticky cups; more permanent adhesives are not under discussion.

So I dropped a TrayInsert grid into a NotesHolder box, stuck them to the existing fixture with snippets of (regrettably black) outdoor-rated foam tape, and there it is:

Acrylic grid bathtub soap tray

You’ll surely not have 3.2 mm acrylic for the grid and 2.5 mm acrylic for the box, but those two linkies have the jawbreaker URLs required to regenerate exactly what I built using the incomparable boxes.py site and you can tweak them as needed.

The general concept had it stick out a bit from the fixture handle to let soap gunk drip into the tub, not down the wall, and to have an easily removable grid for cleaning. I doodled all manner of clever hooks to engage the ceramic handle before coming to my senses; this is a prototype, it may not solve the problem very well at all, so let’s find out if it works before making it better.

The WordPress AI urges me to remind you of the safety issues surrounding DIY projects. IMO, should you need such reminders, they won’t do you any good and you must immediately stop reading this blog.

Fair enough?

2024-07-09
Samsung Microwave Light Improvements

After replacing the gas / humidity sensor in the Samsung microwave, replacing the pair of 40 W (!) halogen bulbs with G8 LED bulbs didn’t pose much of a challenge:

Samsung microwave light – LED-ified reflectorized

Those are not the best bulbs for the application, as they’re allegedly equivalent to 20-25 W halogens, but I had some on hand from a previous relamping project and they seemed promising.

G8 halogens have a flattened section just above the pins that these G8 LED bulbs lack:

G8 halogen vs LED bulb – front view

It’s more obvious from the side:

G8 halogen vs LED bulb – side view

The curvature of the soft silicone LED body magnifies the components to look like they fill all the available space, but a little deft X-acto knife work flensed the body down to fit the microwave’s ceramic socket without exposing any of the electrical innards.

Because the LEDs dissipate only 3 W and barely get warm, I replaced the original translucent glass diffuser panels with (yes, laser-cut) clear 3 mm acrylic, then tucked a strip of aluminized mylar above the bulb to bounce some of the light from the upper chips down where it would do more good. I think it’s possible to melt the acrylic with a stovetop mishap, but we don’t make those kinds of recipes.

They’re not daylight shining on the stove, but they’re much brighter than the halogens at maybe 10% of the power.

2024-07-08
LightBurn Slot Resizing

LightBurn includes a Slot & Tab Resizer tool that automagically finds and resizes joints to adapt a design for whatever material thickness you might be using. To judge from the LightBurn forum threads, it doesn’t deal well with random designs fetched from the Interwebs, which suggests those designs were either never intended for laser cuttery or just badly laid out.

So I fetched a sheep from a typical sketchy source and attempted to resize its slots:

Sheep DXF import – slot resize problem

The tool looks for rectangular shapes within the Tolerance of the Old Material Thickness width, then marks their narrow ends with red highlights and their length with blue. Obviously, not all of the slots we humans see count as slots.

A closer look at one of the body shapes with a slightly larger Tolerance shows some of the problems:

Sheep DXF import – body

Using the Node Editor tool reveals two stray nodes near the bottom of the second slot from the left:

Sheep DXF import – slots

Zooming in and blowing out the contrast:

Sheep DXF import – slot bottom

Manually deleting those nodes doesn’t solve the problem, because two more errant nodes lurk at the top of the slot:

Sheep DXF import – slot top

You probably didn’t notice those at first glance, either. Those nodes may be very close together, but they still confuse the issue.

Rather than tracking down and deleting / adjusting those nodes one by one, you can apply the Optimize Shapes tool to squash the superfluous nodes into straight lines:

Sheep DXF import – optimized

Don’t smooth the shapes or fit them to arcs at this point, because both of those operations will round off the corners.

That may still leave a few nodes requiring manual intervention, as on the face shape:

Sheep DXF import – optimized leftover

But at least the problem becomes tractable:

Sheep and dinosaur flock

As the Bard put it, all’s well that ends well.

2024-07-03