Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
The 3D printed Clover Mini-Iron holder served well over the last decade (!), even after one of Mary’s buddies misplaced the iron during a quilting bee:
Clover MCI-900 Mini Iron holder – melted
She asked for a new holder that put the iron at a higher angle for easier gripping, which required only slight tinkering to boot the OpenSCAD code into the current decade:
Clover MCI-900 Mini Iron holder – higher angle
The letters stand one layer proud of the surface just to see what that looked like. I think it’s a nice touch.
The alert reader will note the cord end isn’t quite snugged into its recess. In normal use, the cord hangs over the edge of the sewing table and pulls the iron into place.
I embiggened the base to fit an aluminum plate from the stockpile, because that same cord tends to pull the holder around on the table. The plate puts enough weight on the silicone rubber feet to hold it firmly in place.
A layer of good double-stick tape strips bonds the aluminum plate to the PETG iron holder, after I once again discovered that craft adhesive sheets do not bond to PETG.
The hidden part of all three LED arrays in the dead garage light looked like this:
LED Garage Light – inadequate heatsink compound
Although the compound was still gooey, there wasn’t nearly enough of it. The few tendrils on the heatsink suggest the LED array had bowed upward, pulled away from the cast aluminum, and eliminated any direct conduction.
A bit of probing showed each LED array had 16 series groups of 4 parallel LEDS, with one group in each array failed open. That group was toward the end away from the inadequate heatsink compound: the LEDs died from heatstroke brought on by neglect.
The Drawer o’ LED Arrays disgorged a bag of surplus LEDs labeled “10 W 9-12 V 750 mA”:
LED Garage Light – epoxy replacement
It’s sitting on a generous blob of steel-filled JB Kwik epoxy that should do a great job of conducting heat. A bag of cheap constant-current supplies is on order.
Amazon has similar “10 W 9-12 V 350-450 mA” arrays.
Try as I might, I can’t get 10 W from those numbers, but I’ve never understood advertising math.
The OXO pepper mill replacing our worn-out pepper mill arrived filled with peppercorns and, during the ensuing nine months, we established its finest grind setting produced bigger pepper flakes than we prefer. I figured there had to be a way to get the ceramic stones just a little bit closer, even though it has no user-serviceable components inside.
So, we begin.
After rinsing out most of the pepper flakes (the remainder appearing in the pictures below) and determining the two obvious screws didn’t release the housing, the Jesus clip on the shaft extending through the peppercorn compartment came under consideration:
OXO Pepper Mill – E-clip on shaft
The washer beyond the clip bears on the black plastic spider. It turns out the thickness of that washer determines the distance between the grind stones at the minimum setting: making it thicker reduces the stone gap and produces a finer grind.
Knowing full well it would be impossible to get the clip back on the shaft in that position, I pried it off.
Spoiler: Don’t do that!
The grind adjustment lever turns the chunky black ring inside the gray housing:
OXO Pepper Mill – grind adjustment rings
Three protrusions on that ring step along notched ramps around the perimeter of the black spider in the clear housing on the right.
The shaft slides out to reveal the spring under the inner stone, with a second washer bearing against the bore of the gray plastic housing:
OXO Pepper Mill – upper shaft parts layout
As a result, the spring tries to push the shaft and inner stone out of the housing (toward the left). The protrusions on the grind adjustment control how far the shaft can move, with the washer + clip locking the shaft to the spider.
Gentle persuasion extracts the chunky black ring:
OXO Pepper Mill – grind adjust slider
The outer stone fits into a recess in the gray housing:
OXO Pepper Mill – outer stone
One might 3D print a washer fitting under that stone to close the gap between it and the inner stone, but the two screw holes interrupt the ledge enough to suggest the washer would be in two parts divided. If I didn’t have a mini-lathe, that’d be the best way to go.
But I have a mini-lathe, so I made a steel washer slightly thicker than the OEM washer under the clip:
OXO Pepper Mill – turning new washer
The OEM washer:
ID 6.7 mm
OD 10.2 mm
Thick 0.6 mm
Not knowing the right answer, I made a 1 mm washer, which is visibly thicker:
OXO Pepper Mill – 1mm vs OEM washer
Which let me reassemble the pepper mill in reverse order, only to establish reinstalling the Jesus clip deep down inside the housing is, in fact, impossible.
Taking everything apart again let me contemplate the inner stone on the shaft, leading to the discovery it could slide very slightly on the shaft. More pondering revealed a slight seam in what I had taken as a monolithic black cap:
OXO Pepper Mill – inner stone assembled
Applying gentle suasion between the stone and the cap with a plastic razor blade enlarged the seam into a gap. Much to my surprise, further prying popped the top off the cap:
OXO Pepper Mill – inner stone cap
Happy dance in full effect!
Removing the screw let everything slide off the top of the shaft:
OXO Pepper Mill – inner stone parts
Freeing that end of the shaft meant I could install the clip on the bench, add various parts while sliding the shaft through the housing, then tighten the screw to snug everything down.
As with most activities, it’s trivially easy when you know the trick.
Whereupon I discovered the new 1 mm washer jammed the two stones firmly together at the finest grind setting, so the correct washer will be somewhere between 0.6 and 1.0 mm thick:
Back to the lathe for a 0.8 mm thick washer
Dismantle pepper mill
Swap washers
Reassemble
Verify smooth turning at finest setting
Fill with peppercorns
Give it a twist
A shower of pepper flakes in a cup:
OXO Pepper Mill – finer grind
The mill undergoes a full qualification test tomorrow morning, but those flakes look much better.
Fun fact: the OXO pepper mill holds 2.0 oz of peppercorns, so we use 0.033 oz = 940 mg of pepper every day.
A three-wing garage light Came With The House in the basement, where it served to light up the foot of the stairs. One of the 48 LEDs in one of the three LED panels began flickering brightly and, over the course of a few days, that panel went dark. The next time I turned on the basement lights, all three panels were dark.
Removing the screw-in lamp base:
LED Garage Light – overview
A closer look inside:
LED Garage Light – detail
The middle of the PCB is darker than the perimeter, with the darkest area around the black inductor standing up near the green filter cap. A blackened lump on the solder side that may have once been an SMD resistor evidently served as a fuse.
All three panels are in wired parallel, so the failed panel reduced the load on the supply, thus increasing the voltage on the remaining two panels enough to kill them off, too.
Worth noting: the black wire goes to the positive side of the LED panel. You can just see the + mark near the two connectors on the left side.
I wired each panel to a lashed-up bridge rectifier with a widowmaker extension cord from a variable transformer controlling the voltage, but none of them responded to the 150 VDC peaks: they’ve suffered Real Death.
The electronics landed in the recycling box and the three heatsinks are now in the Big Box o’ Heatsinkery, where they will surely come in handy for something.
The surprisingly readable 09/21 date code on the case says it’s just over four years old. Similar garage lights now run around ten bucks each and I wouldn’t expect them to last more than a couple of years.
For reasons long lost in our house’s history, two of the zone drain valves on the furnace apparently had something heavy fall on them from a great height:
Furnace zone drain valve – bashed knob
I was certain those knobs were made of brittle pot metal and would snap when I tried to un-bend them.
My weight bench being next to the furnace, I had plenty of opportunities to contemplate conjuring a 3D printed knob similar to the dumbbell nuts, but with the undamaged central part of the metal knob engaging the valve stem to avoid thermoplastic shapes around hot metal.
One can, of course, buy replacement knobs, but where’s the fun in that?
Expecting to cut most of the knob away, I applied needle-nose pliers to the rim and, mirabile dictu, not only did it not immediately snap, I managed to un-bend it into a reasonable facsimile of its original shape.
It wasn’t just beginner’s luck, because I did it again:
Furnace zone drain valve – unbent knobs
Both of those knobs have obvious fractures and aren’t the prettiest things you’ll ever see, but they don’t get a lot of use. I can say, without fear of contradiction, they’re in fine shape.
Apparently we were the first people through a self-checkout lane one morning, because a present emerged before our receipt:
Grocery NCR K5xx printer – boot report
I don’t know whether a K5xx printer runs a descendant of PC-DOS or NCR’s firmware just uses the DOS code page numbers, but it’s been a long time since I had to know any of them.
As Sun Tzu said, “If you wait by the river long enough, the bodies of your enemies will float by.”
Some weeks ago Mary heard a loud bang just as the lights went out. Central Hudson crews arrived shortly thereafter and began examining the transformer serving the group of houses around us. I wandered over to ask questions and learned the bang came from a high-voltage fuse atop a pole 800 feet from our house.
With all the power cables underground, the crews were locating the transformer just upstream of the problem, with the intent of disconnecting it and restoring power to everybody else. That took a few hours for our service, but folks up the hill remained in the dark maybe six more hours.
The paint on the transformer enclosures has been weathering for many decades, but I spotted this one up the hill that looks different from all the rest:
Scorched utility transformer housing
The scorched half of the enclosure pivots upward to reveal the high-voltage disconnect switch, fuses, and low-voltage connections. This one is across the street from our house:
Neighborhood distribution transformer
I think something went badly wrong in there and the transformer overheated to the point of insulation failure, whereupon the short circuit blew the HV fuse half a mile away down the hill.
The Smell of Molten Projects in the Morning 