Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The pivot on the Fiskars Small Detail Scissors (the name is larger than the hardware!) in the bathroom gradually worked loose to the point where I hauled it to the Basement Shop and whacked the rivet with a concave punch:
Fiskars Small Detail Scissors – pivot restaking
Setting the rim of the rivet down a smidge tightened the joint wonderfully well and two oil dots smoothed the action.
I grew up using these concave punches (I have several sizes) to set finish(ing) nails, but apparently real nail punches have a nubbin in the middle to engage the little recess in the nail head which used to be common, back when finish nails arrived well-finished from the factory.
They’re not roll pin punches, either, because those have a different nubbin to support the inside of the pin.
Over the next several days, I’ll be screwing around with trying out different blog themes, because WordPress has “deprecated” the theme I’ve been using since about 2011; it no longer works well with their most recent infrastructure. There being no way to tell how any given theme will look, how difficult creating posts may be, or (in truth) anything about a theme without actually running it, I’ll be doing live-fire exercises while posting odds-n-ends projects from the shop.
Some themes strongly suggest require a logo, so you’ll see this monstrosity until something better comes along:
Logo – Isolated 0D3
Speaking of themes, you’re looking at a “free” blog on wordpress.com, not something I’ve conjured by installing the open-source blog infrastructure from wordpress.org on a server, which means few things you (think you) know about a “WordPress blog” apply. In particular, free blogs on wordpress.com lack access to the universe of themes & plugins applicable to a DIY FOSS installation.
(I think) I’d be perfectly happy to compose posts in Markdown (or some such) and slam them into a static site generator (Hugo / Gatsby / whatever), rather than slog through WP’s GUI editor, but I think my usual post-a-day pace conflicts with the fundamental assumptions of a “static site” generator.
I value blog comments from real people (you all know who you are and I thank you!), but blogspam presents a clear & present danger. Right now, Akismet kills nearly all the hundreds of spam comments per day; it’s obvious any blog comment system must include robust spam filtering. The alternative of, say, running a separate email list for comments seems far more trouble than it’s worth.
I absolutely do not want to sysop my very own blog configuration on a rented server / VPS / Digital Ocean Droplet / whatever. Things like WPengine.com would be attractive, except that this blog’s very long tail generates enough traffic to come very close to the 25 k visit/month upper limit of their “startup” plan; I’m reluctant to pay $100/month for the 100 k visit/month “growth” plan just to host my shop notes.
When I re-capped the HP 10525T Logic Probe, I expected the matching HP 10526T Logic Pulser would require the same treatment. Having finally gotten a Round Tuit, I preemptively pulled it apart to see what was going on inside:
The IC is a Motorola SN7404 Hex Inverter sporting an HP house number in a ceramic flatpack: pin 1 in the upper right, VCC on pin 4, and common on pin 11. The 7716 datecode suggests the chip first saw daylight shortly after single-chip microcontrollers became a nontrivial thing.
The pushbutton switch triggers the expected pulses at pins 10 (purple) and 12 (yellow), with timings controlled by the RC networks:
U1.12 U1.10
The collector output of Q2 is a robust 73 mA pulse through its 62 Ω resistor:
Q2.c
Q1 dumps 15 mA into its 300 Ω resistor:
Q1.C
The push-pull output at the emitter of Q3 and the collector of Q4 looks similar (albeit with some delay cranked in to show the tidy exponential tail):
Q3.e – Q4.c
The manual specifies a 3.0 Ω resistor to ground for Test A, thusly:
HP 10526T Logic Pulser – Test A setup
The output peaks at nearly 3 V to drive a robust 1 A (!) pulse:
Test A pulse
Test B requires a 6.2 Ω resistor driven from 5 V, but a 6.8 Ω resistor came to hand:
HP 10526T Logic Pulser – Test B setup
The downward pulse doesn’t quite reach 0 V (because saturation voltage, etc), so it’s a mere 725 mA:
Test B pulse
HP’s formal setup for Test C requires a totalizing counter to show the pulser produces exactly one pulse for each button push. I just wired up a 47 Ω resistor and eyeballed a few pulses:
Test C pulse – 47 ohm
The lighter 85 mA load through the resistor allows a more rectangular pulse than the 3 Ω resistor. Yup, looks clean to me.
Because the pulser drives its output both low and high with great authority, it doesn’t care what state the external net wants. Here’s what happens with the 47 Ω resistor connected to a 2.5 V supply:
Bipolar pulse – 47 ohm 2.5 V
No matter where the logic family’s threshold might be, the net will experience one downward and one upward transition through it: with the pulser delivering nigh onto an amp, the net’s driver doesn’t stand a chance.
However, the pulser was designed for TTL and DTL (remember DTL?) circuitry, so hammering a 3.3 V microcontroller pin probably isn’t a Good Idea. The notion of keeping a pulser around Just In Case may have reached its end times.
Oh, and about the re-capping. Turns out HP used solid tantalum capacitors and they’re still doing fine after four decades, thankyouverymuch. I put it back together and expect it will continue working forevermore.
For reasons not relevant here, I made another clamp for a magnifying desk lamp and mailed it off in a small box. A few measurements suggested all such lamps share a common design and similar parts, so I duplicated my previous attempt, with some improvements.
On the upside, the same scrap of aluminum plate I used for the previous clamp emerged from the stockpile and, after a session with Mr Disk Sander, sported two square & reasonably perpendicular sides:
Magnifying Lamp Clamp – squaring stock
Rather than rely on my original dimension scribble, I transfer-punched the hole location from my as-built clamp to the stock:
Magnifying Lamp Clamp – locating stem hole
That’s a reenactment based on a true story: the actual punching happened on the bench vise’s anvil surface, with too many moving pieces supported & aligned by an insufficient number of hands.
Drilling the 5/16 inch hole required mounting the Greater Chuck on an MT1 taper adapter for the Sherline:
Magnifying Lamp Clamp – drilling stem clamp
It’s normally on an MT2 adapter for the mini-lathe tailstock, where it handles drills up to 3/8 inch. For the record, the Sherline’s Lesser Check tops out at 1/4 inch and the Least Chuck at 5/32 inch.
Punch & drill the 4 mm cross hole for the clamping screw:
Magnifying Lamp Clamp – drill cross hole
Grab the plate in a toolmaker’s vise, set up some casual guidance, and bandsaw right down the middle:
Magnifying Lamp Clamp – sawing clamp halves
Bandsaw the outline to free the two halves from the stock, then clean up their perimeter:
Magnifying Lamp Clamp – rounded
Saw the clamp clearance almost all the way through to leave a protrusion, then file the scarred kerf more-or-less flat:
Magnifying Lamp Clamp – filing interior
Do a trial fit in my lamp, which lacks the fancy brushed-metal finish of the remote one:
Magnifying Lamp Clamp – trial fit
It holds tight and rotates well, so break the edges and shine up the outside to a used-car finish (“high polish over deep scratches”):
Magnifying Lamp Clamp – surface finish
The inside remains gritty to improve traction on the lamp stem:
The debris field from a recent high-energy collision with a utility pole just north of Red Oaks Mill included another attractive hunk of jewelry:
Nissan Fog Lamp – as found
I asked the guy who runs the towing service across the intersection if this was a “high-performance car / low-performance driver” situation. He said “Nah, the car was a piece of crap.” It apparently collided with the pole after pulling out of the adjacent gas station with entirely too much foot on the throttle; the young driver was last seen having considerable difficulty with a field sobriety test.
Anyhow, the labeling suggests it’s the right-side fog light from a Nissan car.
After removing various shattered plastic mounts and scrubbing off the obvious dirt, the lens didn’t look much better:
Nissan Fog Lamp – as-found lens
The bright triangle is one facet of the hood over the 55 W halogen bulb. The lens seems to be covered with a scattershot coat of gray spray paint or primer, rather than ordinary road grime, applied with surprising uniformity over the entire surface.
A quick wet-sand operation with 400 through 3000 grit paper, then some Simichrome, cleaned it up pretty well:
It’s definitely got a used-car finish: nice polish over deep gouges.
Look closely to see 400 grit diagonal scratches headed upward to the right; I must use 600 or 800 grit paper between the 400 and 1000. I don’t care about optical clarity, just knocking back the worst of the damage will suffice.
Methinks it would look pretty with internal RGB LED lighting, although the optics are obviously set up for a halogen filament just under the edge of the internal hood. If I get it just right, the thing could project a beam across the room …
After four years, I finally had occasion to use the blue label cartridge, only to have the tape refuse to feed. The mess on the tongue sticking out shows the result after I forcibly pulled the tape from the cartridge:
Cheapnified Brother Label Cartridge – exterior
The proximate cause was a fold in the imaging tape takeup path causing the driven spool to stop turning:
In the genuine cartridge, the base tape (with the sticky side and the colored side) feeds from the lower right directly into the assembly pressure roller. The transparent cover tape feeds from the spool in the lower left, up around the imaging tape supply spool, has the image fused to it, and is then pressed against the base tape on the assembly roller.
Update: Per david’s comment, the cartridges are even more complex than I thought! The printer has sense pins matching a group of cartridge holes to determine (at least) the tape size & orientation. See the pix added below.
Despite using the same cartridge body, the cheapnified tape path is entirely different. The base tape now feeds from the spool in the lower right through what should be the cover tape supply reel, around the imaging film supply spool, has the image fused directly to it, then passes out through the assembly pressure roller.
The cover tape is completely missing!
It turns out the cheapnified cartridges don’t bother with lamination. Instead, the printhead presses the imaging film against the top of the base tape, leaving the black image exposed to the elements. The assembly roller does nothing, apart from pulling the base tape through the cartridge.
Now that I know what to look for, the visible difference is the orientation of the base tape. A cartridge with the correct innards feeds the base tape with the colored side + image facing away from the long side of the cartridge. A cheapnified cartridge has the color + image facing the long side, with the major benefit of making the advertising look more appealing:
Fake Brother TZ cartridge – Amazon image
A genuine Brother cartridge would print the image on the bottom of the tape in that picture, so you’d see the blank side of the tape in that picture.
The “Amazon Marketplace” being what it is, I assume any pictures will not, in general, have much in common with what you actually receive, but at least I now know which ones to reject out of hand.
Update: The PT-1090 label printer has cartridge sensing pins:
Brother PT-1090 Labelmaker – sense pins
And the cartridges have corresponding holes, although the printer doesn’t sense all of them:
Brother PT-1090 Labelmaker – cartridge ID holes
Despite that, cheapnified cartridges are still cheapnified.
I learn something new every day around here! Thanks!
The rod turned freely in its underground anchor, but the nut is apparently frozen to the rod. I deployed the bolt cutter on the cable and hauled the carcass into the Basement Shop:
Pole anchor – nut loosening
Steeping the nuts with Kroil for a few hours relaxed them enough to submit to gentle suasion, whereupon the cable sproinged as the last nut released the clamping force:
Pole anchor – hardware
As far as I can tell, the clamp hardware dates back to the pole’s original installation in 1940 and is in fine, if not pristine, shape.
The bolt shanks have an oval section matching the holes in the plate, so the bolts don’t turn and the crew needs only one wrench. They don’t make ’em like they used to!
I have no idea what I’ll do with these things, but they’re entirely too nice for the steel recycling bucket.
The Smell of Molten Projects in the Morning 