Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
Six sticky traps have been out in Mary’s Vassar Farm onion bed from mid-April through mid-July, collecting onion maggot flies, other flying insects, and a bunch of shredded leaf mulch. Having just replaced all the sticky sheets, these are the results so far:
PXL_20230711_215255180 – VCCG Onion Maggot Trap F
PXL_20230711_215229538 – VCCG Onion Maggot Trap E
PXL_20230711_215159950 – VCCG Onion Maggot Trap D
PXL_20230711_215129817 – VCCG Onion Maggot Trap C
PXL_20230711_215041012 – VCCG Onion Maggot Trap B
PXL_20230711_215002214 – VCCG Onion Maggot Trap A
Each image is the front and back of a single sticky sheet flipped over left-to-right; I did not keep track of the original trap locations.
If you need the original camera images to get enough pixels for itemizing the smaller dots, let me know.
Daubing urethane adhesive into each pocket, sliding a tiny magnet atop the goo, and flipping them over onto a sheet of plastic atop the surface plate to let them cure went about the way you’d expect. Given the state of my fingertips, however, I was not about to fiddle with the phone / camera / anything, but it really did happen.
The final result:
Lathe Chuck Stops – on-lathe storage
The alert reader will notice the slight gap under the left leg of the first orange stop, which provides a good introduction for a few things that should happen differently the next time I do something like this.
To my credit, I got all but one of the 54=3×6×3 magnets into their pockets in the same orientation. That’s gotta count for something and, hey, that orange stop sticks to the chuck just fine.
That one also suffered from my failure to switch the Axis UI to metric units before touching off the Z axis at 0.1 mm, thereby putting the Z=0.0 level 2.53 mm below the surface. Fortunately, the 3 mm MDF baseplate prevented that error from creating three pockets in the tooling plate, although it did produce holes instead of pockets in the stop.
I dropped the magnets into the thru-cut stop on the surface plate and dabbed some adhesive atop the magnets to bond them into their holes. This worked fine and led me to suspect the easiest way to make these stops would be to just laser-cut the holes and skip the whole CNC thing.
The disadvantage of cutting the holes through is that adhesive will inevitably ooze out around the magnet and mess up the bottom surface of the stop. Sticking both the stop and the magnets onto kapton tape seems like it should seal well, but liquid always finds a way.
In any event, the two-part urethane adhesive (JB Plastic Bonder) expands slightly as it cures, which is great for gap filling and not so good for precision bonding. With the pockets in the other 17 stops arranged open-side down, the magnets held themselves firmly to the plastic sheet atop the surface plate and the expanding urethane pushed the acrylic stop upward, leaving the magnets standing slightly proud of the stop’s surface:
Lathe Chuck Stops – protruding magnet
Not by much, mind you, but not what I wanted, having painstakingly cut the pockets 2.2 mm deep for a 2.0 mm magnet.
Next time, dot some slow-cure clear pouring epoxy in each pocket, put the stop on the surface plate with the pocket facing up, then drop the magnet in place. The magnet pulls itself into the pocket, the epoxy doesn’t expand, any overflow will fill in over the magnet, and anything sticking out can be sanded off.
The fixtures worked well and aligned perfectly on the Sherline’s tooling plate. The 0.1 mm outset around the stops in the chipboard probably wasn’t needed, although the total repeatability seemed to be around 0.2 mm and pocket position errors are visible only on the smallest (red) stops:
Lathe Chuck Stops – misaligned pocket
All in all, this turned out pretty well. Next time will be even better!
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:
Laser cutting the Danger Zone coasters with the proper kerf offset for a good fit produced a pile of waste pieces from the other side of the kerf that seemed too nice to throw out. A bit of rummaging in the Basement Shop Warehouse Wing produced a battered magnetic sign that fell off the side of another truck and some casual searching suggested the material was laser-cuttable, whereupon this happened:
Laser-cutting magnetic sheet
The trick is to cover the label side of the sign with adhesive sheet and the refrigerator side with blue painter’s tape, thereby simplifying the inevitable cleanup. Cutting through the adhesive produced poor results, perhaps due to molten adhesive or the sign material (which is almost certainly non-laser-safe PVC, alas) flowing into the cut and contaminating the process. Cutting through the blue tape worked reasonably well, albeit with a disconcerting shower of sparks.
The cutting pattern is the shape outline inset by about 0.5 mm.
Peel off the blue tape, remove the adhesive cover layer, align the outermost shape, press it down, add the rest, then admire the results:
SCP Cognitohazard – refrigerator magnets
The obvious difference in the “filament” size comes from two different kerf offsets, both on the order of 0.15 mm. It makes a big difference in narrow objects!
The Autonomous Object coaster created its own pile of scrap and you can see the gaps created by the mismatched kerf offsets:
SCP Autonomous Object refrigerator magnet
Not works of art, but they came out nicely given where they started.
I recently replaced the hack-o-matic icemaker + fountain pump cooler with a LightObject Q600 water chiller, an entirely uneventful process. The Q600 has a back panel “aviation connector” with an alarm output for water flow (more precisely, lack thereof) or over / under temperature: pins 1 and 3 are closed during normal conditions and open during alarms (and when the power is off).
I finally wired the chiller into the OMTech 60 W laser’s internal water flow switch circuit, so that should either flow sensor have a problem with the water or the chiller detects an out of bounds temperature, the laser won’t fire.
You may recall the laser’s HV power supply arrived with its Water Protect input jumpered to ground, which I then wired to the lid interlock switch to (presumably) reduce the likelihood the replacement power supply will fail hot. The laser’s water flow switch goes to the Ruida controller’s WP input, where it behaves as it should.
Pin 2 of the chiller’s alarm connector is not connected to anything, so I added a safety ground wire for no good reason:
Laser Water Chiller – safety ground wire
The dent in the evaporator tube (upper left) is worrisome.
While I had the side panel off, I jammed a strip of closed-cell foam around the base of the compressor to silence a truly spectacular rattle:
Laser Water Chiller – compressor vibration suppression
I think the three mounting screws (yes, of these two: one up, one down, for no reason I can see) are looser than they should be, but I’m reluctant to tip the whole thing over with a tank full of water to get at the nuts / bolt heads on the bottom.
The connectors have a twist-lock notch that you must release after removing the screw (on the far side) holding the shell to the body:
Laser Water Chiller – connector shell keyway
I repurposed a USB cable from the Big Box o’ Cables, wrapped with enough silicone tape to fill the cable clamp:
Laser Water Chiller – connector closeout
In retrospect, I should have paired the red + green and black + white wires, but nobody will ever notice. The drain wire carries the safety ground from pin 2 to the shielding, not that it matters. Both ends of the cable have identical connectors.
The laser cabinet has a convenient hole, albeit just a bit larger than required, which now has a simple adapter plate with the proper flats:
Laser Chiller Alarm Connector Plate
The blue ring is the same size as the hole, so as to ease lining it up, and the red perimeter surrounds the connector with strips of good double-sided foam tape for maximum sticktivity. Done in clear acrylic from the scrap pile, the platform’s internal lights give it that subtle blue-white hi-tech glow:
Laser Water Chiller – laser connector installed
The doubled-up cable ties on the water hose barb connectors are a Good Idea™ due to the somewhat higher pressure of the chiller’s water pump. The bottom of that recess had traces of water on it and, of course, having a hose pop off its barb is a Bad Thing™.
The new connector is wired in series with the internal flow switch, using a trio of grossly overqualified silicone-filled splices:
Laser Water Chiller – laser flow switch splices
I did not connect the safety ground from the chiller to the laser’s frame, because they do not share a common breaker circuit and I have better things to do than chase ground loops.
For whatever it’s worth, the gray cable that came with the laser might also be a repurposed USB cable, too: it has two fat wires and two thin wires, although it’s not wearing USB livery.
The laser is happy when the chiller is running and unhappy when it’s off, so life is good.
Chipmunks zip into drain pipes when they detect even a slight threat:
Chipmunk peering from drainpipe
When I installed the drain pipes for the gutters & retaining wall along the driveway, I added a grate plug to keep critters from setting up housekeeping in what must look like an extensive cave network, although later experience showed I must clean debris out of the plug more frequently than I expected:
Driveway drain – fountain
I didn’t glue the PVC pipes together, because I knew they’d need adjusting, so it was no surprise when the last section of pipe shifted enough to open a small gap, probably because my lawnmowing passes always proceed from right to left over the pipe:
Chipmunk Refuge – shifted drain pipe
The front yard chipmunk immediately claimed the pipe and zipped into the opening whenever we met on my way to the mailbox.
When I reconnected the pipe, the chipmunk knew something had gone wrong and started some exploratory excavation in about the right spot to find the missing tunnel entrance:
Chipmunk Refuge – missing gap
Not being one to rebuff the humble, I decided to make the world better:
Chipmunk Refuge – site overview
It’s a short section of PVC pipe with a wood plug in the far end to keep what I grandly call “our lawn” from filling it up. I bandsawed a disk from a scrap of inch-thick lumber that used to be a door and introduced it to Ms Belt Sander often enough to make it a snug push fit in the pipe.
Some decoration seemed in order:
Chipmunk Refuge – decorated end plug
Which gives the place a nice, homey look:
Chipmunk Refuge – installed
Now, we’ll see whether the critters enjoy it as much as I did.
A chance encounter in the acrylic scrap box led to a radioactive einstein:
SCP Earrings – Radioactive einstein
That was so easy it’s gotta be either criminal or sinful.
A few test on scrap acrylic while tweaking the SCP warning label geometry showed only a few work well at such a small scale:
SCP Earrings – einsteins
The mirror in the lower right got cut from the back side, making it the mmmm mirror image of the others.
IMO these would look and cut better in 1.5 mm acrylic, but it seems edge-lit acrylic only comes in 3 mm sheets.
They are absurdly fragile across the waist, but my admittedly limited exposure to fine jewelry suggests durability ranks low in the selection checklist.
The Smell of Molten Projects in the Morning 
