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: Oddities

Who’d’a thunk it?

Check Your Zero

A recent OpenSCAD mailing list discussion started with an observation that the dimensions of printed parts were wildly different from the numeric values used in the OpenSCAD program that created the STL. Various folks suggested possible errors, examined the source and STL files to no avail, and were generally baffled.

Finally, a photo conclusively demonstrating the problem arrived:

Caliper – digital vs. analog scale

Note the difference between the digital readout and the analog scale printed on the body.

Turns out it’s his first digital caliper: he simply didn’t realize you must close the jaws and press the ZERO button before making any measurements.

We’ve all been that guy. Right?

FWIW, our Larval Engineer can probably still hear me intoning “Check your zero” every time she picks up a caliper or turns on a multimeter. Perhaps she’ll think fondly of me, some day. [grin]

2017-03-18
Credit Union Email: Phishing or Not?

The Credit Union recommends we practice “Safe Computing” with this helpful advice (clicky for more dots):

HVFCU – Safe Computing – sketchy URL

The link leading to that page was on their website, but the page is on trabian.com, whoever they are. Should I trust the links on that page to return me to the credit union site or not?

Here’s their definition of “phishing”:

HVFCU – Phishing description

Having just switched to “paperless statements” at the Credit Union, a recent email prompted me to look at my statement. Let’s start by seeing where the email came from:

HVFCU – Statement email – From address

Huh.

It claims to be from the credit union, but does its actual address (insofar as anything concerning email can be actual) of statement2web.com sound a little phishy to you, too?

Well, let’s look at the full headers, which I can do because, yo, 1337 H4X0R. Here’s a snippet from the bottom of the stack:

HVFCU – Email detail header

Huh.

So the email started from statement2web.com and bankshotted off kbmla.com. Further up, the headers show it rattled through pobox.com and eventually arrived in my inbox. As far as I can tell, it never touched its alleged starting point of hvfcu.org at any point in its journey.

Quick: phish or no phish?

Of course, it’s a perfectly innocent message from the credit union, but it contains every single warning sign we’re supposed to notice in spam or phishing emails, complete with a clicky link!

[heavy sigh]

2017-03-12
Cheap WS2812 LEDs: Another Failure

A few days after epoxying a replacement WS2812 RGB LED into the base of the 21HB5A and, en passant, soldering a 3.5 mm plug-and-jack into the plate lead for EZ removal, the top LED failed.

21HB5A – Audio plug cable

In this case, it also failed the Josh Sharpie test with bad encapsulation sealing:

WS2812 LED failure – ink test patterns

Here’s a view from another angle, with a warm-white desk lamp for a bit of color:

WS2812 LED failure – ink test patterns – 2

Those patterns took a few days to appear and also showed up in some, but not all, of the previous failing LEDs.

Although I have no idea what’s going on, it’s certainly distinctive!

An envelope of RGBW LEDs, allegedly with SK2812 controllers, has arrived from a different eBay supplier, so it’s time for an upgrade.

2017-03-11
Squirrel vs. Bird Feeder

After months of attempts and (occasionally) spectacular failures, one of the backyard squirrels managed to climb aboard the bird feeder:

Squirrel on bird feeder

The shutter closes when more than two cardinals and a titmouse perch on the wood bar, so the squirrel didn’t get anything. However, back in 2008, one of that critter’s ancestors mastered the trick:

Not a Squirrel-Proof Feeder

Since then, I’ve raised the feeder about five feet and inverted a big pot over two feet of loose PVC pipe around the pole.

Given the number of squirrel-training videos on Youtube, however, it’s only a matter of time until the critters put all the tricks together!

2017-03-04
Rail Trail Blockage

This big branch must have landed with a mighty thump across the Maloney Road entrance to the Dutchess Rail Trail:

DCRT – Maloney Rd – tree down – 2017-02-20

Yeah, some jerk ran a snowmobile up the slope around the tree, leaving a pile of dirt on the ramp. So it goes.

We took an alternate route, I emailed The Right Folks, and (most of) the tree vanished two days later; evidently, the property owner gets to deal with everything to the left of the line of trees.

2017-02-26
MicroMark Bandsaw: Blackened Table
The really bright LED worklights I added to the MicroMark bandsaw produced plenty of glare from the raw aluminum table top:

USB Gooseneck Mount – on bandsaw

No good deed goes unpunished, I suppose.

While rooting around for something else, I rediscovered my bottle of Birchwood Casey Aluminum Black (basically selenium dioxide) that’s intended for touchup work on small parts, not blackening an entire aluminum plate. Well, having had that bottle forever, it’s not like I’ll miss a few milliliters.

If this didn’t work, I could always sand the table down to the original aluminum finish.

So I applied a sanding block in hopes of smoothing the tooling marks:

MicroMark Bandsaw – sanded table

Looked pretty good, I thought, so:
- Wipe it down with alcohol (per the bottle instructions)
- Slather on a generous dose of Aluminum Black
- Let that chew on the table for a minute
- Rinse off with water, wipe dry
- Perch atop the furnace for thorough drying
- Spray with Topsaver oil, wipe down
- Put it back on the bandsaw
Aaaaand it looks great:

MicroMark Bandsaw – blackened table

Well, in terms of metal finishing, that blackening job looks downright crappy. Aluminium Black is intended for decorative work and will surely wear quickly on the bandsaw table, but it’s entirely good enough for my simple needs: the glare from those lights is gone.

After I took the picture, I blackened the brass screw in the slot. Came out a weird mottled green-bronze, might look antique in a different context, suits me just fine.

Done!
2017-02-10
Forester: TPMS FTW, Redux

Now I know the Forester’s TPMS icon blinks on 1000 feet from a cold start with 12 psi in the offending tire. I returned home and pulled this from a sipe in the left rear tire:

Road debris – blade fragment

It’s atop a 0.1 inch grid.

The flat side on the right rode tangent to the tire surface, recessed slightly below the tread, and pretty much invisible inside the sipe. Of course, the point punched through the tire’s steel belt and let the wind out, ever so slowly.

I initially thought it was a utility knife blade fragment, but under the microscope it looks more like a saw blade tooth. It’s obviously been kicking around on the road for quite a while; back in the day, they occasionally swept the roads, but that was then and this is now.

Makes me glad I didn’t buy four new tires after the last flat. I suppose installing two plugs in the same tire counts as a net loss, but they’re small, widely separated injuries and that’s how it’ll roll.

For the record: with 14 k miles on the tires, tread wear = 2/32 inch of the original 6/32 inch depth.

Those tires should last another 30 k miles at our current pace, although I expect more random debris will kill one stone cold dead before that.

2017-02-08