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

Storm Door Latch Lube

Storm door latch parts

Our old house has storm doors with brass latch bolts and brass strike plates. Brass-on-brass is nicely self-lubricating, unlike the steel-on-steel contraptions available these days, but of late our back door hasn’t been closing smoothly.

I fiddled with the door closer’s tension and release point to no avail, then (re)discovered that a dab of PTFE lubricant on the latch and strike plate makes the storm door close exceedingly smoothly. The base grease is clear and doesn’t make a black mess of things.

Duh.

Maybe everybody knows that and perhaps I knew it at one time.

I wrote about rebuilding the strike pull and shaft cam of these latches as CNC projects in my Digital Machinist column. Naturally, the replacement latches available in the local hardware stores didn’t fit the door, so the simplest course of action was some quality shop time.

2009-02-28
Analon Slide Rule
Whenever I do anything even slightly out of the ordinary with magnetics, I must drag out my trusty Analon slipstick to make sure I haven’t lost a dimension.

Analon slide rule – front

Go ahead, you verify that the area inside a BH hysteresis curve is proportional to power loss in a given transformer core. I’ll wait…

Analon slide rule – back

My recollection is that I bought it in the Lehigh University Bookstore in the early 70s, but that doesn’t square up with the Analon’s history: they should have been out of circulation by then. I’m pretty sure I didn’t get it in high school, extreme geek though I was, and it’s for damn sure I wouldn’t have bought one after graduation. Come to think of it, if the LU Bookstore wasn’t among the last bastion of Analon holdouts, where would you look?

Over the decades I’ve penciled in a few handy dimensions they didn’t think of. Unlike most of the 600 597 (plus one in the Smithsonian) Analons in the wild, this one actually gets used, so it’s not New-In-Box (which means you collectors need not suffer from involuntary hip motions). It’s also not as grubby as it looks: I didn’t spend a lot of time futzing with the scans.

Anyway, that’s called beausage and it enhances the value.

Works that way with other antiques, right?

Links:
Yeah, OK, it’s a Slide Rule Gloat…
2009-02-27
Power Outlet Contact Failure

Burnt outlet expander

Ordinary AC power outlets have fairly robust contacts, designed to last basically forever. I have no idea what the actual design life might be, but it’s rare to have an AC outlet fail.

This one did…

It’s an outlet expander at the end of an extension cord that provides six outlets. I’d installed it at my parent’s house (I was their go-to guy for electrical things, of course) and everything was fine. One visit involved rearranging some appliances and the adapter went nova when I plugged something into it.

Me being their go-to electrical guy, I’m pretty sure this gizmo didn’t experience a whole bunch of mate-unmate cycles in my absence. Most likely it was defective from the factory, so sticking a plug in once or twice was enough to break the contact finger.

Detail of burnt socket

Here’s a contrast-enhanced detail of the outlet in the lower-right of the top picture. The broken finger bridged the brass strips carrying the two sides of the AC line in the left side of the compartment.

Blam: brass smoke!

Oddly, the fuse didn’t blow. It was pretty exciting to have a small sun in the palm of my hand until the contact finger fell to the bottom of the compartment.

The bottom picture shows the offending finger. It’s pretty obvious what happened.

Errant contact finger

I’ve read of folks applying silicone lubricant (spray, perhaps) to their AC line plugs to reduce the mating friction in the outlet. While that sounds like a good idea, I think it’s misguided: you don’t want to reduce the metal-to-metal contact area by lubing it up with an insulator. In any event, that sliding friction ensures the contacts have a clean mating surface with low resistance.

Maybe use some Caig DeoxIT, but not an insulating spray!

For what it’s worth, do you know that the durability of an ordinary USB connector is 1500 cycles? That’s far more than PCI backplane connectors at 100 cycles. Some exotic high-GHz RF connectors can survive only a few dozen cycles.

Moral of the story: don’t unplug your stuff all the time. Use switches and stay healthy.

This took place many years ago, so the picture quality isn’t up to contemporary standards.

2009-02-25
Verizon FiOS: What’s the Real Price?
So FiOS has finally arrived here in the hinterlands and the latest teaser deal is $70/month for 10/2 Internet and anywhere-in-the-US VOIP. The ad mailers always tout the blazing speed (although that’s not what they offer in the teaser) and voice clarity.

But there’s an asterisk: the prices are always “plus taxes and fees”.

So I called the FiOS order line (877-896-2263) with two simple questions:
- What, exactly, are those taxes and fees?
- What, exactly, will they add up to each month?
After five minutes of telling the nice man everything they already know about me and giving him permission to read their own records of our account, I managed to push him off his script long enough to get a word in edgewise.

He tells me that the taxes and fees depend on my exact location and the services I sign up for. I point out that we’ve just established my address and he should know what services he’s offering, soooo what’s the price?

We go around and around:
- He says the only way to find out is to sign up and get my first bill
- I refuse to buy something without knowing the price
Eventually he offers to transfer me to billing, where he says (and I have no reason to doubt) that they’ll certainly tell me the same thing. Sounds like a good idea to me, if only to get to the next screen. He’s obviously miffed that I’m not following my lines in his script and just buying FiOS like a good sheeple.

I hear the usual beeps & boops, a snippet of their on-hold blather, and dead silence. Ten seconds later, the call disconnects and I get the usual “If you’d like to make a call, please hang up and dial again” message.

They don’t care. They don’t have to. They’re the phone company.

Right now we’re getting 13/2 Internet from Cablevision (aka Optimum Online) for $50 and a Verizon landline for $25.

Let’s see: slower Internet and marginally cheaper phone service, plus the asterisk. Not a compelling value proposition in our situation. But, then, we’re cheapskates.

Incidentally, the “taxes and fees” make up $10.61 of this month’s $25.09 phone bill. I have good reason to believe that if we buy two services from Verizon, the fees will add up to $20 or so. But there’s no way to find out without buying them first, of course.

I’m seriously thinking of killing the damn landline and struggling along with VOIP and our $5/month cellphone.

Update: Today’s mail brings an even better teaser with a different phone number: 877-896-5322. It’s still $70/month for a one-year “agreement”, but now with free activation and a $100 cash card and they guarantee the rate for two years. The kickbacks push it just under $60/month for the first year. Still has that asterisk, though. Not to mention that the offers just keep getting better and better … I’m sure the early adopters are astonished at Verizon’s sliding incentive scale.

Update 2: If you ignore the flyer and sign up for FiOS via the Verizon website, you get an additional $5/month off and you don’t have to deal with Verizon customer service. That brings it down to $55 plus the dreaded asterisk… I wonder what next month’s mail will bring?

Update 3: Another flyer and the offer is still $70/month, free activation, and $100 cash back. Somehow I think FiOS uptake around here isn’t living up to their expectations.
2009-02-23
Bad Gas!
No, not that kind!

Over the last several years, more or less coincident with the switch from MTBE to ethanol, all of my small internal-combustion engines have stopped working with stored gasoline, even when it’s treated with StaBil, even for just a few months.

After plenty of putzing around, pouring in fresh gasoline has solved the problem in every engine.

For example, I’d left the snow thrower’s tank empty after tracking down the bad gas problem in 2007. I filled it with gas from about November when we did the last of the leaf shredding; I think I’d dosed it with Sta-Bil, but in any event that’s relatively young gas by my standards.

The blower didn’t even cough when I leaned on the starter button; not a single pop. I fired a dose of starting fluid up its snout and it still didn’t fire. At all. Period. As a friend puts it, starting fluid should wake the dead.

Pulled the plug, blew compressed air into the cylinder to dry it out, went out for a can of New Gas, drained the Old Gas, filled the tank, and it fired right up. Surges a bit at idle with no choke, but I can deal with that.

Lessons learned:
- You cannot store ethanol-treated New Gas for more than a month or maybe two, tops, at least for use in small engines.
- Sta-Bil doesn’t work on New Gas. I’d love to be proven wrong, but this whole bad running thing began with well-treated gasoline stored in a closed container.
- There is no longer any way to have an emergency gasoline stash on hand so you don’t have to go out in the FFC (that’s Freezing obscene-gerund Cold) dawn for a fresh tank.
Even with fresh gas, the engines surge under light load, which is a classic symptom of an air leak around the carburetor: lean running. But in all the engines? And with no detectable leaks? Even after replacing the gaskets?

As nearly as I can tell, the problem stems from the 10% ethanol added as an oxygenate. The additional oxygen reduces pollution in modern engines, but causes small engines (at least the ones without electronic mixture control, which are all of mine) to run very very lean.

The cheap solution seems to be setting the engine at about 1/3 choke for normal running. That richens the mixture enough to make the engine happy, but without farting black smoke out the muffler.

Although I no longer keep a 5-gallon can of gas for emergencies (which I’m sure will come back to haunt me one of these days), I do keep a gallon with dose of StaBil for the yard equipment.

Update: As of late-Feb 2009, that entire Cornell website has been dead since I posted the link. If it never comes up again or the link stays broken, here’s the punchline. The link pointed you to their evaluation of Cherokee Trail Of Tears beans, with this review from someone with *cough* experience:

This is my favorite dry bean for black bean soup. It’s not called “Trail of Tears” for nothing. If you walk behind someone who’s eaten a mess of these beans, your eyes will be burning. It’s a very gassy bean.

This Internet thing isn’t ready for prime time; stuff just softly and suddenly vanishes away.

Update 2: Cornell is back online again. It seems their servers got pwned… after their desktops got infected. But, eh, they’re running Windows, what do they expect?
2009-02-19
Vanquishing the Power Vampires

Every gadget comes with its own battery charger wall wart, every single one of which dissipates a watt or two even when it’s not charging. Add ’em up, multiply by $2 per watt per year (check your electric bill; that’s closer than you think!), and realize that you could afford some nice new tools just by unplugging the things between charges.

But that’s too much trouble and, really, AC outlets aren’t meant for that many mate/unmate cycles. I had one contact fall loose inside a power strip a while ago and the carnage was spectacular.

What to do?

Recharging Corner

Find an otherwise unoccupied flat spot (or build a shelf near an outlet), buy two or three Power Squid adapters (you don’t need surge suppression for this assignment, so get ’em on sale cheap), plug all your chargers into the Squids, and turn everything off with a single switch when you’re not charging anything.

Bonus: You certainly have some low duty cycle power tools that always have dead batteries when you need them. Plug ’em into the Squid you use most often for other batteries. That way, they’ll get a boost whenever you charge something else, which should keep ’em up to speed.

I set this tangle up before Power Squids existed, so I just plugged a bunch of Y-splitters into an ordinary power strip. It makes for a fearsome tangle of cords, but at least it’s out of the way atop the never-sufficiently-to-be-damned radon air exchanger in the basement.

2009-02-17
Digital Camera Resolution: It’s Not The Dots

Overview of the scene – 8 MP image

A rule of thumb for cameras is that more glass is better, so I’ve always been skeptical of those little bitty chips o’ glass in front of all those pocket-sized camera CCDs.

A while ago I took some shots with my Casio EX-Z850 at various resolutions, chopped out a chunk with some good detail from the middle of the images, and resized (cubic interpolation) the smaller ones to match the 8 MP image. The exposure was automagic: 1/200 sec at f/7.4. Zoomed as far as the optical zoom would go, hand-held ’cause at that shutter speed it’s OK, sharpness and contrast one click higher than the default.

As nearly as I can tell, there’s only a slight difference between 8 & 6 MP, enough to be noticeable at 4 MP, and it’s getting on toward icky at 2 MP. The picture isn’t any bigger because I wanted to preserve the actual dots in the 8 MP image.

Resolution Test – Shield

Notice the weird color gradations in the shields with bright primary colors. This was hand-held, so the camera reached the same image conversion conclusions each time, starting with different physical pixels. A bit of rummaging turns up the Island Coffee Co logo at http://www.islandcoffee.net/.

Just to show that resolution doesn’t matter in real life, check out the snail. Zoomed all the way out, macro focus, 1/125 f/2.8 (wide open), hand held, resized as above.

Resolution Test Images: Snail

As nearly as I can tell, the 2 MP image is the only one that’s noticeably worse and it’s still just fine. The other three are different, but even the 2 MP one isn’t bad.

Moral of the story: lots o’ dots is good, but beyond a few MP it just doesn’t matter. I think 4 MP is the sweet spot, based on an entirely insufficient sample, with 8 MP if you’re planning tight cropping. Otherwise, save 2 MB per image: 8 MP -> 4-5 MB, 4 MP -> 2-3 MB.

The other High Truth: lots of light is a Good Thing. You get really crappy pictures when there’s not enough light, but it seems that’s where all the interesting stuff happens.

Update: Uploaded the PNG version of the shield resolution test, as the JPG was fairly crappy, plus 8 MP overviews of the scenes. The text is antialiased and looks awful when you zoom in, but the whole point is to show the actual dots produced by the camera: there aren’t that many dots for the letters.

Snail overview – 8 MP image

2009-02-14