Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
It lacks the flange required to seal the O-ring against the outside of the bin, but I can fix that:
Can-o-worms – sleeved valve
It’s a chunk of PVC pipe faced to the proper length, bored to fit the valve body, then gooped in place with acrylic caulk.
Snug the nut inside the bin and it’s all good:
Can-o-worms – new valve installed
The original valve depended on having a smooth plug turning inside the outer shell, but years of grit scarred the interface enough to produce a slow drip. It also had the annoying mis-feature of aiming the opening inward, between the bin legs, where a jug didn’t quite fit.
The water heater valve depends on compressing a smaller O-ring against a seat inside the body, which may tend to clog with crud. We added a mesh filter to hold back the worst of the gunk, so this is in the nature of an experiment using free hardware.
I finally managed to whack the mini-lathe’s carriage stop handle with the chuck, prompting a quick repair:
Carriage Stop – handle epoxy clamping
I probably should have epoxied a rod into the recess under the handle, seated in a drilled hole into the hub, but let’s see how long this quick-n-dirty version lasts.
While I had the hood up epoxy was curing, I lasered a block of edge-lit acrylic to replace the credit card shims:
Carriage Stop – spacer
Which turned out to be one itsy too thick. Rather than sand / machine it down, the step over on the left grew a little brass shim:
Carriage Stop – spacer and shim
Both pieces depend on snippets of adhesive sheet to hold them in place, which seems reasonable because they’re always in compression. That also eliminates the hole and pin I originally thought would be necessary; living in the future is just grand.
Having occasionally been in need of a lathe chuck stop, I finally cleared that project off the heap:
Lathe Chuck Stops – demo setup
These are definitely not up to commercial standards, but also don’t cost fifty bucks each. A trio of 4×2 mm neodymium disk magnets stick the stop to the chuck (and to each other) with enough force to hold it there, but not enough to make removing it a hassle.
Trace the right-side jaw, clean it up, put the tip a known distance from the origin, make a circular array, and draw a comfort circle the size of the chuck OD.
The stop geometry comes from a hull wrapped around a circle a few millimeters larger than the 4 mm magnet (out 20 mm from the center) and a circle at the center sized so the hull clears the jaws:
Lathe Chuck Stops – LB layout
Then a small circle at the center allows me to drop the stop atop a known coordinate and rotate it around the circle, because the XY coordinate center is not at the geometric center.
I cut out a few chipboard samples to verify the sizes, a few more from scrap acrylic to set up the pocketing operation, then half a dozen of each in cheerful kindergarten colors:
Lathe Chuck Stops – on-lathe storage
The 5 mm stop is obviously too fragile for commercial success, but I figured it’ll survive long enough around here. Worst case, I can make another handful as needed.
Although I have laser-engraved pockets in plywood, a few experiments in acrylic confirmed the surface finish is terrible and the depth control is iffy, at best. Given that I need a 2.2 mm deep pocket in 3 mm acrylic, a CNC mill seems the right way to poke the pockets:
The bathroom ceiling fixture has a nightlight position that we use occasionally, but eventually the little 7 W Christmas Tree bulb failed and I installed this hulk from a box of CFL bulbs a friend scrapped out after switching to LED bulbs:
MaxLite CFL – overview
I never tested whether it actually drew 3 W, but, hey I could feel good. Right? Right?
Anyhow, this one failed after a few years, too. The “bulb” envelope looked like it might make an attractive blinkie or glowie, so I decided to harvest it.
The candelabra screw base felt loose and popped off with a push:
MaxLite CFL – overflow cap
Perhaps they chose the envelope before finalizing the circuitry?
This is why you need a lathe in your shop:
MaxLite CFL – lathe cutting
It wasn’t particularly well centered, so that was done dead slow and finished with a few hand turns of the chuck. Obviously, I need a crank for the spindle.
The rest of the circuitry is pretty well packed under that tall cap:
MaxLite CFL – circuitry
Pulling the PCB out revealed the tube wiring:
MaxLite CFL – tube wires
Cut the wires and chuck it up again:
MaxLite CFL – envelope turning setup
Turn dead slow again until it breaks through:
MaxLite CFL – envelope breakthrough
Then finish by hand:
MaxLite CFL – tube and envelope
It’s too cute to throw out, but … sheesh you can see why recycling this stuff is so difficult.
For whatever it’s worth, I replaced it with a 3 W LED candelabra bulb that is way too bright.
Having acquired some thick-wall (1 inch OD, ¾ inch ID) aluminum tube, making the LED heatsink and lens holder for a running light generates a lotless scrap. A new doodle gives the dimensions in a rather Picasso-ish layout:
Running Light – dimension doodles
The back end of the tube gets turned down to 23 mm OD and cleaned up to 19 mm ID, then scored to give the epoxy something to grip:
Front Running Light – Heatsink shell scoring
The front end gets bored to 22.5 mm for the lens holder and has its OD cleaned up to 25 mm:
Front Running Light – finished shell
Clean up the end of a ¾ inch rod to 19 mm OD, knurl it a little to increase the OD ever so slightly and improve its griptivity, slice off a bit more than 10 mm, butter it up with JB Weld epoxy, and shove it into the shell with its front end aligned and its back end sticking out:
Front Running Light – epoxied plug in shell – rear
Face off the back end and the front end looks fine as assembled:
Front Running Light – epoxied plug in shell – front
Grab it in the Sherline mill’s three jaw chuck to:
Drill & tap the M3 central hole for the stud holding the circuit plate to the back end
Drill 1.6 mm blind holes for the circuit plate pins
Drill 2 mm through holes for the LED wires, 60° apart
Which looks like this from the front:
Front Running Light – drilled heatsink – front
And like this with the circuit plate screwed & glued to the rear:
Front Running Light – circuit plate mounted
Clean up the OD of some ¾ inch PVC pipe to 25 mm, bore it out to 23 mm.
While the Sherline is set up, drill a pair of 2 mm holes in the lens holder for the wires, aligned so they’ll match the heatsink holes.
Because we live in the future, laser-cut the rear cap from some edge-lit acrylic with a black inner disk:
Front Running Light – PVC tube – end cap
Cutting that cap with the notch included is now trivially easy, compared to the previous machining.
While swapping chuck jaws I realized I didn’t have to pile them on a shop rag atop the lathe headstock, no matter how neatly cut those rags might be:
Lathe chuck jaw holder – installed
It’s three layers of MDF cut to hold all six jaws from the 4 inch 3 jaw chuck, stuck together with wood glue.
You really need only four sockets: one empty for the jaw you just removed, then work your way around the chuck. But, hey, MDF is cheap and I usually remove all three at once anyway.
When it starts walking away, it’ll sprout silicone feet.
Anything would be better than just taping some gel filters to the front of the bare photodiode package:
Laser output – photodiode kludge
Right?
I heaved the slab of ½ inch black acrylic left over from the Totally Featureless (WWVB) Clock into the laser cutter and, two passes at 90% power later, had a somewhat lumpy 32 mm donut with an 11 mm hole in the middle. Because acrylic is opaque to the IR light from a CO₂ laser (which is why it cuts so well) and black acrylic is opaque to visible light (which is what the photodiode is designed for), this is at least as good as an aluminum housing and much easier to make.
Chuck the donut into Tiny Lathe and bore out the hole:
PIN-10D photodiode filter holder – boring ID
When it’s a snug fit to ½ inch brass tube (about the same size as the photodiode’s active area), flip it around, and bore the other size out to fit the photodiode case.
Ram the tube in place, grab the large recess, and center the tube:
[Edit: Got that backwards: I bored the big recess first.]
Skim most of the OD down, then, because I am a dolt forgot to put a spacer in there, flip it around again, get it running true (the chuck aligns the flat side):
Even though they’re pretty much transparent to thermal IR, a focused IR laser beam cuts them just fine. The little tab at 6 o’clock (remember round clocks with hands?) keeps the cut circle from falling out.
Drill & tap for an M3 setscrew to hold the photodiode in place:
PIN-10D photodiode filter holder – parts
Put them all together:
PIN-10D photodiode filter holder – assembled
I must conjure a better mount for the thing, because this is way too precarious:
PIN-10D photodiode filter holder – test install
Early results suggest it works better than the previous hack job, without ambient light sneaking around the edges of the filter pack.
The Smell of Molten Projects in the Morning 
