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

Splinting an Umbrella Strut
One of the ribs in the six-passenger umbrella we keep in the van snagged on something and snapped its fitting on the spreader strut:

Umbrella strut – broken connector

This being wonderful engineering plastic that cannot be solvent-bonded, epoxy is the only adhesive that will work. However, those joints undergo tremendous stress in a deployed umbrella, so a bare epoxy joint won’t have enough strength for the job. What to do?

Wonder of wonders, when I got the umbrella into the Basement Laboratory Repair Wing, I discovered:
- The not-quite-round strut fitting stub slipped right into a short brass tube from the heap and
- Just enough of the fitting remained on the rib to anchor the tubing
A silicone tape wrap kept most of the epoxy inside while it cured:

Umbrella strut – epoxy curing

Clearing off a few blobs made it all good:

Umbrella strut – brass tubing splint

We don’t play golf, but such a big umbrella keeps most of the rain off two people; it’s a tchotchke from back when Mary worked at IBM (hence the color scheme). We call it our “six-passenger” umbrella because it looks about that big when we deploy it…
2012-10-16
Bicycle Mobile: New Windscreen Mic Ball

The bikes stand upright inside the van and the helmets ride on the floor with all their stalks sticking up. This usually works out well, but on our last trip my helmet rolled under my bike and rubbed the foam ball surrounding its mic against the chain, producing a result so awful that I had to install new foam.

For posterity, here’s the current state of the electret mic and its mount:

Electret mic on bike helmet boom

The foam comes from a sheet of Sonex acoustic foam baffle, snipped into a reasonable approximation of a ball, with a slit deep enough to surround the mic, and a cable tie holding it closed:

Foam mic ball on bike helmet boom

For what it’s worth, I’ve found that excessive wind noise correlates with too much mic gain. The mic rides about a finger’s width from the corner of my mouth, I talk at a normal volume, the amp supplies about 20 dB of gain, and we have no trouble with wind noise. The amp gain depends on the mic sensitivity, so your results will certainly differ; these mics came from the heap with no specs whatsoever.

I suppose wind noise also depends on the bike’s speed, but when I’m going that fast I don’t have enough brain or lungs left over to hold a conversation…

2012-10-12
Sink Soap Dispenser Pump: Nozzle Fitting

The absurdly heavy pump nozzle atop the kitchen sink soap dispenser seemed more wobbly than usual. Some investigation suggested the fitting atop the plastic pump has gotten smaller, which may be due to having the nozzle wobble around on it.

In any event, a wrap of Kapton tape snugged it up just fine:

Sink soap dispenser pump

We’ll see how long that lasts; this thing may be nearing the end of its useful life.

2012-10-11
Sienna Anti-Theft Blinky Light

Our Toyota Sienna arrived with a blank cover plate where a fancier model would have a switch. It seemed a shame to let that space go to waste, so I popped the plate out, rummaged around in the heap, found a small circuit board with a blinky LED that just exactly fit the space available, and drilled a suitable hole:

Sienna anti-theft blinker – inside

When it’s installed in the van, it looks and acts just like the security system we don’t have. For all I know, that plate was for the security system control, so perhaps it’s an exact match!

Sienna anti-theft blinker – bezel

The batteries last about two years, a few months later I notice the lack of blinkiness (it’s hidden behind the steering wheel in my normal driving position), and eventually I replace the corroded batteries. This time, I had to replace the entire battery holder; things got pretty nasty in there.

As I recall, the PCB came from a fancy “greeting card” mailed to me by the Business Software Alliance, with the implied threat that if all my paperwork wasn’t up to par, my use of potentially unlicensed software would blow up in my face. That was back in the day when mailing something that pretended to be a bomb was considered a cute joke and when I actually ran more than one Windows PC.

Linux is a lot more relaxing…

2012-10-10
Utility Knife Blade: Corrosion Thereof

This little utility knife lives in my belt pack for those occasions when I need a sharper blade than my long-suffering Swiss Army Knife can provide. Alas, I must have sliced up something awful in the recent past:

Corroded mini utility knife blade

Although the knife frame is slightly magnetic, it’s also reasonably noncorrosive and cleaned up pretty well after some Topsaver and wire-wheel brushing activity:

Mini utility knife – somewhat cleaned

Whew!

For whatever it’s worth, this is the same knife that made it through the Washington DC “security scans” that eventually confiscated Mary’s Swiss Army Knife. She didn’t look any more guilty than I did…

2012-10-09
Vise Handle Bumpers

Bench vises (not vices) have heavy steel handles that clank when the ball end slams into the hub. You can fix that by slipping suitable rubber washers over the balls on each end:

Vise handle bumper

After which the handle gives off a pleasant thump and won’t nip a careless finger.

This is an old trick and certainly not original with me; the occasion being that I just replaced the old and much-abused washers which were letting the clank through again. IIRC, a retail package consisting of both red rubber garden hose washers and black rubber O-rings followed me home from a tag sale, so I used both.

2012-10-04
Faucet Washers

The slop sink in the rental house developed a drip and, unlike our kitchen faucet, required only a new washer. Of course, choosing the right size from that assortment posed a bit of a problem:

Slop sink valve with washers

The old washer is in the upper right; you can see the indentation from the valve seat.

There’s a variety of sizes & shapes; these represent just the closest matches. I have no idea what 3/8, 3/8R, and 3/8L might signify, but they’re all slightly different, some with conical cross-sections that may also be slightly different. Worst case, of course, you can sand down the rim of a too-large washer to make the diameter come out right.

[Update: a table of sizes mentioned in the comments.]

The washer just in front of the old one has information molded right into the back: GOLDEN STATE 10¢ 1/2. Now there’s a show of confidence in price stability that you don’t see much any more!

I found one that fit snugly in the recess of the valve stem, turned the screw tight, and it’s all good.

2012-10-03