Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
With RF projects looming on the horizon, now seemed like a good time to restock the silver-mica capacitor supply:
Silver-mica capacitor – assortment
That’s 150-ish little brown envelopes, found on eBay in the lowest-entropy state I can imagine, with about 11 pounds of caps delivered for a bit under $5/pound.
The envelopes bear date stamps from the mid- to late-60s:
Silver-mica capacitor – 188 pF 0.5 pct – envelope
I think these came directly from the Electro-Motive Mfg Co production line or QC lab, because some of the envelopes have notes about “WE”, “Bell Labs”, and suchlike. They seem to be special-production items, not the usual caps from your usual distributor.
The values and tolerances are weird beyond belief:
Silver-mica capacitor – 6160 pF 0.5 pct – on envelope
If you’re taking notes, 6160 pF lies halfway between the 6120 and 6190 values in the E192 series.
And, yes, that’s a cap with ½% tolerance (forgive the bright-red color imbalance):
Silver-mica capacitor – 6160 pF 0.5 pct – detail
Most of the caps are 1%, which is kinda-sorta typical for silver-mica. Then you find something unbelievable:
Silver-mica capacitor – 22.8 pF 0.1 pct
Stipulated, I’ve lived a sheltered existence. Have you ever seen a 0.1% tolerance cap? The assortment has more of those, scattered throughout the range.
Regrettably, the entire decade from just over 300 pF to just under 3000 pF has gone missing: somewhere out there, someone has another box from the room that housed this collection. So it goes; given the plethora of values, I can always make series-parallel combinations to get what’s needed.
This appeared on The Mighty Thor’s phone during a Squidwrench meeting:
BofA Phishing
“To maintain a secure banking environment” seems diagnostic of a scam.
Discouragingly, some of our banks still send emails with clicky links using third-party mail servers, so checkonlineinfo.com doesn’t seem any more suspicious than, say, Schwab’s customercenter.net.
I found this antique on eBay for (somewhat) under HP’s 1980-era $35 price:
HP 09872-60066 Digitizing Sight – overview
The prevailing price for HP 09872-60066 Digitizing Sights seems to be $100 and upwards, with outliers in both directions, so I just couldn’t pass it up.
Anyhow, the fiber optic pipe still works just like it did, back in the day:
HP 09872-60066 Digitizing Sight – text target
The small dot in the middle is actually a paint-filled indentation on the bottom surface:
HP 09872-60066 Digitizing Sight – bottom detail
With the bottom flat on the target, the relayed image is in perfect focus:
HP 09872-60066 Digitizing Sight – top detail
The bezel recesses the top surface by 25 mil to protect the imaging plane.
OK, it’s a gadget gloat; I have absolutely no intention of ever chucking a piece of paper in the plotter and digitizing any points.
A long long time ago, we bought a kitchen spatula that’s served us well ever since:
Spatula Search – original
To give you an idea of how old that poor thing is, the back of the handle bears a Japan stamp. I’ve re-set the rivets several times, the blade has rusted as badly as you think, and we recently, very reluctantly, decided it has passed its best-used-by date.
The 3 x 4.5 inch blade is 19 mil = 0.45 mm plated carbon steel, stiff enough to remain flat and springy enough to bend a little, with a 9 inch = 230 mm steel handle ending in a plastic overmold.
These days, it’s essential to the cutting, flipping, and serving of the morning’s omelet-like substance, made of eggs, bacon, veggies, green leafy things, plus this-and-that, in the cast-iron pan. Mary chops the disk into quarters with the reasonably sharp edge, maneuvers the reasonably bendy blade under each quarter, flips them over, tops with bacon & cheese, pauses for consolidation & melting, then pops them onto plates. Yum!
Omelet in cast-iron pan
So we set out to buy a replacement.
Here’s what we’ve tried and rejected so far:
Spatula Search – overview
I’ve used this one for many years to flip pancakes on a succession of non-stick griddles, a service at which it excels. The edge isn’t sharp enough to cut the green-and-leafy and the completely inflexible blade cannot be maneuvered under the omelet quarters:
Spatula Search – heavy solid plastic
This one gets deployed for burgers and their ilk, also in the cast-iron pan. The blade, although sharp enough, is completely rigid:
Spatula Search – heavy slotted metal
On the other paw, a slightly concave 7 mil = 0.18 mm spring steel blade is much too thin and, well, springy. Although very sharp, you cannot apply enough cutting force without suddenly bending the blade and, if the omelet quarter isn’t positioned exactly right, the blade will bend underneath it and dump breakfast on the stovetop. The alert reader will notice a missing weld between the blade and the bottom wire handle:
Spatula Search – thin spring steel
This very thin plastic blade has similar problems with poor cut-ability and excessive flexibility:
Spatula Search – thin springy plastic
This one looked really promising and worked almost perfectly. Regrettably, its nylon blade bears a 400 °F rating and the bottom of the omelet reaches nearly 450 °F. You can see what happens to the reasonably sharp edge as it scrapes across the pan:
Spatula Search – heavy slotted nylon
The omelet cooks at the temperature it cooks at, which part of the specifications is not subject to further discussion.
So, we’re stumped. Having trawled the usual online and big-box stores, we’ve been unable to find a replacement. Simple steel blades aren’t available. Trendy silicone-bonded stainless steel blades combine the worst of all worlds: won’t cut and won’t flip. Pretty nearly anything you don’t see above seems obviously unsuitable for our simple needs: too big, too small, or too melty.
We’ll consider all recommendations and suggestions! Thanks …
New Cadillacs have thin white LED running lights along the front edges, with angular chromed trim below:
Cadillac running lights
Their SUVs have matching vertical-stripe taillight / markers; it’s obviously a stylin’ thing. If it weren’t for the power, I’d run LED strips along the edge of the fairing & seat frame on our ‘bents.
The Smell of Molten Projects in the Morning 