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: Home Ec

Things around the home & hearth

Balans Chair Re-footing
I’ve been using what’s now called a Multi balans chair since shortly after it came out in the 80s, during which time the plastic feet have worn flat:

Balans chair foot – foot wear

By now, the wood bases ride on the floor, which is a Bad Thing I should have fixed long ago:

Balans chair foot – wood wear

The newer Multi chairs have rolling endcaps, but AFAICT that’s not a retrofittable thing.

The feet have no obvious way to get them out, but after I saw how thin the plastic had become on one foot, some experimental carving solved the problem:

Balans chair foot – OEM foot removal

A large bolt threaded into the crude hole provided enough griptivity to yank the feet out:

Balans chair foot – removed feet

With measurements in hand, I picked up a quartet of furniture leveling feet with M10 stems and tee nuts that exactly fit into the recesses:

Balans chair foot – tee nut fit

I generally buy from sellers who include measurements in their descriptions, although I no longer believe any unit-measurement prices. Most of the time the sizes come out close enough to reality for my simple needs.

The stems were, of course, too long, but that’s easy to fix:

Balans chair foot – cutting stem

The saw does yank the stem down at the last moment, but cutting slow & steady thins the steel and reduces the drama to manageable proportions. Fitting a scrap of wood exactly under the screw would be a much better technique; be it so moved.

With the chair set to the mid-angle position I normally use, the feet meet the floor almost perfectly:

Balans chair foot – straight foot contact

At the steepest angle, things get skewed:

Balans chair foot – angled foot contact

Applying my nearly perfect hindsight, I got a set of swiveling feet and found an appropriate scrap of wood:

Balans chair foot – swivel foot cutting

Zero drama!

Which looks exactly like it should with the chair at the steepest angle:

Balans chair foot – swivel foot contact

The chair now sports two pairs of feet:
- Straight feet on the rear
- Swivel feet on the front
Now, to see how they survive on a chair, rather than motionless furniture.

If you have any idea why the WordPress AI image generator would come up with this, let me know:

Balans chair foot – WP AI image

That’s not hallucination, it’s just plain irrelevant.

For the record, we also have a couple of equally ancient Variable balans chairs.
2024-06-03
Improvised Table Leg Latch

While setting up the small table I conjured from scrap, I discovered one of the folding legs no longer had a latch to keep it from folding. Whether it never had one or the latch got lost along the way, there’s no time like the present:

Table leg latch – installed

The bolt I put there in place of the joint rivet precludes a smaller latch along the lines of the simple steel loop on the other leg, so I figured I may as well go large and, with that much surface area, plywood will work just as well as steel for my simple needs.

It’s a topless, bottomless box from the infinite supply at boxes.py, here seen with its halves being glued at right angles on an aluminum bracket:

Table leg latch – gluing

When those set, I glued & clamped them together in situ, then wrapped the whole mess with what’s basically high-strength friction tape to encourage it to not come too far apart under the inevitable stress when the leg tries to fold with a pile of stuff on the table.

We’ll see how long this survives; if past experience is any guide, it’ll be a while.

The WordPress AI image generator has a shaky grasp of both human anatomy and the blog topic:

Woodwork design by Escher. What is that interesting tool? So many arms, all with nightmare fuel anatomy!

2024-05-31
Sillcock Faucet Alignment Wedge: Getting the Angle Right
A pair of frost-free sillcock faucets arrived to replace the house’s leaky and un-repairable hose bibs. The faucet must be mounted at a 5° angle to let the water drain out when it’s closed:

Everbilt Frost-Free Sillcock faucet – installation

One might expect the Alignment Wedge included with the faucet to have a 5° angle. Because I can both measure and math, it has a 1° angle.

Well, I can fix that.

Start by scanning the bottom (widest side) of the wedge and apply GIMP’s Select by color tool:

Sillcock faucet alignment wedge – GIMP color selection

After a little manual cleanup in Quick Mask mode, apply a 1 mm inset to ensure it snaps around the pipe, convert the selection to a path, export it as an SVG image, and import it into OpenSCAD to cut the angle:
```
// Sillcock faucet alignment wedge
// Ed Nisley KE4ZNU - May 2024

MaxThick = 5.0;
Tilt = -5.0;

PlateOA = [60,40,MaxThick];   // XY = original angle plate size

difference() {
  linear_extrude(height=MaxThick,convexity=5)
    offset(r=-1.0)
      import("/mnt/bulkdata/Cameras/2024/Shop Projects/Sillcock Faucets/Sillcock faucet angle washer - outline.svg",
             center=true);
   translate([-PlateOA.x/2,-PlateOA.y/2,MaxThick])
     rotate([Tilt,0,0])
        cube(PlateOA,center=false);
}
```
The solid model goes into PrusaSlicer for duplication & slicing:

Sillcock faucet alignment wedge – PrusaSlicer layout

And comes off the printer looking just about like you’d expect:

Sillcock faucet alignment wedge – OEM vs printed

The far side of both wedges are 5 mm tall, but you can see the difference four more degrees makes in the front.

It’s even more obvious from the edge:

Sillcock faucet alignment wedge – on pipe

The wood siding where these will fit is perfectly vertical, so getting the wedge angle right isn’t really optional.

I must drill the existing hole in the sill plate out to 1-1/8 inch to clear the pipe fittings, plus the wood around the screws holding the current bibs to the wall will surely need some buttressing, but all that’s in the nature of fine tuning.

FWIW, this was the first 3D print after the move and I’m happy to say the M2 had no any need of adjustments.

The WordPress AI image generator apparently ignored the post text and produced a stylin’ picture of an arched bathroom faucet over a rimless sink, which I shall leave to your imagination.
2024-05-30
C-Power KK-800A Calculator Dress Panel Re-gluing

Long ago, I got Mary a cheap “desk calculator” with a vital function: it beeps cheerfully with each keypress. Nothing lasts forever and the aluminum dress panel around the keys has been gradually working its way loose.

So, we begin …

Gingerly remove the panel, un-bend and flatten it, lay it on the scanner, and cover with black paper:

C-Power calculator keyboard cover

Blow out the contrast, threshold the image, do a little touchup, and get a binary mask:

C-Power calculator keyboard cover – mask

Import into LightBurn, trace and discard the image, do some shape optimization, add 0.2 mm to the height & width of one key, propagate those dimensions to other keys (Make same width and Make same height FTW), cut a paper prototype to verify the fit, iterate until it drops neatly into place, cut an adhesive sheet, then peel & stick:

C-Power KK-800A keyboard – adhesive placed

The dress panel was held in place by what was once a quick-setting gooey glue that had long since fossilized. Although it gave up on the aluminum, it was not going to come off the calculator body without more struggle than seemed warranted.

So I stuck the new glue atop the old glue and hoped for the best. You can see traces of the old glue bead through the sheet:

C-Power KK-800A keyboard – adhesive ready

Lay the dress panel in place, burnish between the rows & columns, and it looks about as good as it ever did:

C-Power KK-800A keyboard – restored

If the adhesive sheet also gives up on the aluminum, I’ll try some fancy 3M 300LSE adhesive.

The WordPress AI image generator heard I like keys, so it spat out some keys for my keyboards:

Calculator keyboard – WP AI image

The piano keys seem familiar, the thing in the middle looks eerily like a PDP-11 front panel, and … could that be a folding keyboard in the distance next to an 8-track player from a car dashboard?

2024-05-27
Sears Sewing Machine Table Latch Fix

The Sears sewing table (Model 853-9635, not that you have one) wrapped around Mary’s Kenmore machine has extension surfaces on both ends:

Sears Sewing Machine Table – overview

The foot panel is secured by a simple wood latch that fell off the left side:

Sears Sewing Machine Table – stripped hole

Having some recent experience with this sort of thing, but not wanting to work under there, I waited for a pause in the sewing, then tried to remove just the hinged piece under the top surface. It turns out the joint is glued-and-screwed, so removing the two obvious screws didn’t do anything.

Dismounting the top surface at its other hinge and hauling the whole assembly to the Basement Shop showed this wasn’t the first time the latch had pulled its pivot screw out of the wood:

Sears Sewing Machine Table – stripped hole detail

The reason the screw pulled out of the top hole / slot is obvious when seen from the edge:

Sears Sewing Machine Table – screw obstruction

That’s one of the screws holding the piano hinge in place, but AFAICT the original latch screw also went right across that hole with maybe three threads engaging the wood.

Moving the pivot half an inch to one side won’t make any difference, so I figured I could sink a threaded insert into the wood. I’d rather use the drill press, but sometimes you gotta do what you gotta do:

Sears Sewing Machine Table – insert drilling

The combination square gets the drill eyeballometrically perpendicular to the end piece and the drill lies flat on the (underside) of the table surface. Seeing the bit line up with where the hole had to be was confirmation this would be successful; all I had to do was proceed slow-n-steady with the brad-point bit and stop when the tape hit the wood.

The insert screwed in as expected, without any collisions:

Sears Sewing Machine Table – insert installed

I drilled the wood latch to clear an M5 screw on the drill press, dabbed the screw with threadlocker, and reassembled everything on the bench for curing:

Sears Sewing Machine Table – latch installed

The extension surface on the right side of the table has an identical latch that hasn’t failed yet, but we agreed a preemptive repair is uncalled for.

The WordPress AI image generator is delivering much less jank, even if the result has little to do with the actual post:

Sears Sewing Table – WP AI image

Don’t think too much about the shadows, nor the lack of a treadle for what looks a lot like an early Singer Featherweight machine.

2024-05-24
Home Depot Glacier Faucet Re-alignment

The kitchen sink faucet came from the Home Depot Glacier line:

HD Glacier Bay kitchen faucet – overview

A “FastMount” push-and-turn nut secures the central pillar to the deck, although it had worked loose since it was installed some years ago. After retightening the nut, however, the faucet spout and handle remained loose, which I eventually figured out was due to the central pillar having worked loose from the plastic body inside the spout.

The solution involved releasing the FastMount nut, pulling the whole affair out of the deck, and tightening the threaded pillar into the body. After a few false starts, I applied a pair of grippy leather gloves and a firm grasp to twist the pillar another quarter turn into the body, after which it installed properly:

HD Glacier Bay kitchen faucet – realigned

The mark on the far left shows how much I twisted the pillar:

HD Glacier Bay kitchen faucet – misaligned front mark

If I don’t tell anybody, they’ll never notice.

I fear this will not be permanent, in which case I must disconnect all the plumbing, take the faucet into the Basement Shop, and have my way with it. Most likely this will involve thread locking compound applied to parts that aren’t visible without a complete disassembly.

For the record, the setscrew securing the faucet handle to the valve fits a 2.5 mm hex wrench, aligned just about parallel to the handle rather than perpendicular to the rear surface:

HD Glacier Bay kitchen faucet – handle setscrew alignment

In comparison to the never-sufficiently-to-be-damned American Standard faucet in our previous kitchen, the spout does not depend on rotating O-ring seals, because the valve sends water to the integral sprayer through a flexible hose. Although the spout does have an O-ring at the bottom, it serves to keep casual splashes out, rather than pressurized water in.

With a bit of luck, this will work forevermore.

2024-05-16
Samsung Microwave Gas Sensor Teardown

With the microwave back in operation, I thought I might learn something about the failed gas sensor:

Figaro TGS880 – base

Given that much information, finding the datasheet for a Figaro TGS880 sensor didn’t require much effort. In case you were wondering, the replacement sensor has no trace of branding or identification.

The sensor element has a resistance varying with gas concentration, for a variety of test gases I hope our kitchen never contains in such abundance:

Figaro TGS-880 Gas Sensor – response plot

The measurement circuit:

Figaro TGS-880 Gas Sensor – measurement circuit

I betcha the microwave waits for an order-of-magnitude resistance drop from whatever the starting value might be, then calls it done.

The belly band holding the steel mesh to the plastic base is no match for a Dremel slitting wheel:

Figaro TGS880 – opening

As the saying goes, Sensoria est omnis divisa in partes tres:

Figaro TGS880 – teardown

A closer look at the sensor element:

Figaro TGS880 – interior

The granular surface does not get along well with the 5× digital zoom required to fill the phone’s sensor, but you get the general idea:

Figaro TGS880 – element detail

The heater measured 30 Ω on the dot and the sensor was an open circuit on the 100 MΩ range. Connecting the heater to a 5 V supply dropped the sensor resistance to 800 kΩ @ 50 %RH and a warm breath punched it to about 2 MΩ. That’s with an ohmmeter because I haven’t yet unpacked the Electronics Bench, but seems far above the spec of 20-70 kΩ in air.

So it’s still a sensor, even if it’s not within spec.

The WordPress AI-generated image for this post is … SFnal:

Figaro TGS-880 Gas Sensor – AI generated image

My pictures apparently aren’t up to contemporary blog standards …

2024-05-14