The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Machine Shop

Mechanical widgetry

  • DIY CPAP Mask Liner

    DIY CPAP Mask Liner

    Mary cut out a simple cloth liner for her ResMed F20 CPAP mask (a.k.a. “cushion”) and snipped away at the fabric until it felt about right. I scanned the result and turned it into a bitmap mask (which is entirely different from a CPAP mask):

    Mask liner - scanned
    Mask liner – scanned

    Given that as a start:

    • Import the scanned image into LightBurn
    • Fair a few curves around the perimeters by hand, rather than attempting to trace the thing
    • Rationalize the sizes
    • Make it symmetric
    • Cut a few prototypes while tweaking the fit

    Which leads to a pattern like this:

    CPAP Mask Liner - F20 knit - spline fit
    CPAP Mask Liner – F20 knit – spline fit

    The rectangular upper part forms a simple eyeshade that also keeps minor leaks from disturbing her sleep. Your mileage may vary, depending on how much you toss and turn during the night.

    We found the fit depends on the fabric, with woven fabric requiring a taller opening:

    CPAP Mask Liner - F20 knit woven - LB layout
    CPAP Mask Liner – F20 knit woven – LB layout

    The engraved legend verifies I used the proper design for the fabric:

    Laser cut CPAP Mask Liner - F20 - knit fabric
    Laser cut CPAP Mask Liner – F20 – knit fabric

    The opening has tabs holding it in place while cutting, at least until we get this down to a routine.

    Then make enough for a while:

    Laser cut CPAP Mask Liner - F20 - production
    Laser cut CPAP Mask Liner – F20 – production

    The usual woodstove odor vanishes after half a day sitting atop the clothes washer. Putting them in a mesh bag and tossing them into the regular wash refreshes them after use.

    The LightBurn SVG layouts as a GitHub Gist:

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  • Shower Faucet Handle Rebuild & Tightening

    Shower Faucet Handle Rebuild & Tightening

    The shower faucet handles have been getting looser, but once a decade seems reasonable. This time around, however, the setscrews had dug themselves so far into the splined plastic fittings that they had run out of thread:

    American Standard Shower Handle rebuild - gouged setscrew sockets
    American Standard Shower Handle rebuild – gouged setscrew sockets

    Wipe out the crud, clean out what’s left with alcohol to encourage stick-to-it-ivity, and fill the cavities with JB Kwikweld epoxy:

    American Standard Shower Handle rebuild - epoxy fill
    American Standard Shower Handle rebuild – epoxy fill

    When it cures, file a flat across the sockets:

    American Standard Shower Handle rebuild - flatted
    American Standard Shower Handle rebuild – flatted

    Reinstall in reverse order with a dot of NeverSeez on the setscrews for good measure.

    Just so you don’t have to look it up, this is what the cold water faucet innards looked like a decade ago:

    Shower faucet valve stem
    Shower faucet valve stem

    Ought to be good for another decade, right?

  • World War II Dog Tag Layout

    World War II Dog Tag Layout

    Quite some time ago, I hammered out G-Code to engrave ersatz dog tags for a Cabin Fever demo:

    Cabin Fever Dog Tag
    Cabin Fever Dog Tag

    A dozen years later, making a World War II dog tag is a whole lot easier:

    John Q Public - WWII dog tag
    John Q Public – WWII dog tag

    Well, “easier” if you allow laser engraving in white-on-black Trolase using a font intended to mimic a typewriter.

    Close enough, methinks.

    Which comes from a simple layout:

    John Q Public - WWII dog tag - LB layout
    John Q Public – WWII dog tag – LB layout

    The outline traces a scanned image of my father’s tag, fitting a few hand-laid splines around the curves:

    John Q Public - WWII dog tag - spline curves
    John Q Public – WWII dog tag – spline curves

    I generated a random serial number based on my father’s draftee status (he was in his early 30s during his South Sea Island tour) and state of residence; my apologies to anyone carrying it for real. His blood type was A and (I think) the religion code marks him as “Brethren”, a common group in my ancestry.

    Given the outline, various plastics, and a laser, other effects become possible:

    WWII dog tag outline test
    WWII dog tag outline test

    It might come in handy for something, someday.

    The LightBurn SVG layout as GitHub Gist:

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  • Lift Chair Foot Risers

    Lift Chair Foot Risers

    The fuzzy felt feet on the lift chairs raised them enough to slide both floor lamp bases underneath with the backs in the upright state, but reclining the chair with the light more than halfway back along the side of the chair crunched the lamp base.

    Rather than print taller fuzzy feet, which takes a long time, I knocked out two quartets of laser-cut risers:

    Lift Chair Foot Riser - installed
    Lift Chair Foot Riser – installed

    They’re six layers of 3 mm MDF or plywood:

    Lift Chair Foot Riser - assembled
    Lift Chair Foot Riser – assembled

    The LightBurn layout makes one riser:

    Lift Chair Feet Extenders - LB layout
    Lift Chair Feet Extenders – LB layout

    The upper two discs become two rings and two pads, with the lower two disks forming the middle layers. The ring ID clears the chair foot and the pad OD fits into the existing printed fuzzy felt foot. The two cuts making that happen leave the thinnest imaginable ring of MDF in place.

    The tiny circles cut holes for 11 mm snippets of 1.1 mm hard steel wire aligning the layers:

    Lift Chair Foot Riser - locating pins
    Lift Chair Foot Riser – locating pins

    Assembly sequence:

    • Tap two pins into a ring
    • Butter the ring with yellow wood glue
    • Slide the other ring over the pins
    • Butter
    • Slide a disk over the pins
    • Drive a pin into a pad
    • Butter
    • Slide the other pad over the pin
    • Butter
    • Slide a disk over the pin atop the pads
    • Butter one of the disks
    • Slide the disks together over all three pins
    • Tap all pins below their surface

    Make two and clamp them together to ensure everything sticks firmly.

    Repeat to make four risers

    Install, recline, and enjoy not hearing a mysterious crunch from the lamp base.

    The alert reader will note the 6 mm stack of two pads leaves a slight gap above the printed foot. Turns out the recess is 5 mm deep and I decided to just live with a 1 mm gap down there.

  • Universal Socket to Quarter-Inch Hex Adapter Stack

    Universal Socket to Quarter-Inch Hex Adapter Stack

    Being that type of guy, I wanted to salvage a loooong square-head bolt from the utility pole stub formerly holding up the mailboxes, which would require a few gazillion turns of its square head with the Adjustable Elephant Wrench. After verifying I couldn’t just hammer the mumble thing through the pole, I gave a few turns of the Universal Socket on a ratchet:

    Universal Socket Wrench
    Universal Socket Wrench

    It’s intended for goobered hex heads up to 1-¼ inch, but the pins slide down around pretty much anything that sticks out and jam against the shell, so it’s handy for those last-ditch extraction events.

    After verifying doing this by hand would occupy me until just before the heat death of the universe, I followed Mad Phil’s signal connector adage: “If you can get to BNC, you can get to anything.”

    Some rummaging produced this unsteady mechanical ziggurat:

    Universal Socket to quarter-inch hex - adapter stack
    Universal Socket to quarter-inch hex – adapter stack

    From bottom to top:

    • Universal Socket with ½ inch square drive socket
    • 1/2 inch square drive to ¾ inch hex
    • 19 mm (close enough to ¾ inch) 12-point socket to ⅜ inch square drive socket
    • ⅜ inch square drive to ¼ inch square drive socket
    • ¼ inch square drive to ¼ inch hex drive

    Then stick the teeny end into the hand drill, rig engines for reverse running, and whine away on that bolt, which obligingly backed right out.

    After the fact, I found the obviously missing ¼ to ½ inch square drive adapter hiding in the Drawer o’ Sockets:

    Universal Socket - short adapter stack
    Universal Socket – short adapter stack

    Which doesn’t make any more sense, but is less likely to fall apart under normal use.

    Aaaaand one more adapter makes this possible:

    Improper square drive adapter stack
    Improper square drive adapter stack

    That’s a 50 mm socket turned by ¼ inch hex drive in four easy steps, although I’m reasonably sure it still won’t get the idler bogies off my armored personnel carrier.

    The stray adapter steps down from ½ square to ⅜ square, should a need for a breaker bar occur during eyeball surgery.

  • Laser Engraved Fabric

    Laser Engraved Fabric

    This is more along the lines of searing the fuzz, rather than actual engraving:

    Laser Engraved Fabric - cotton knit
    Laser Engraved Fabric – cotton knit

    The top row is 15% power at 400 mm/s, the bottom is 25% power, and the fabric was a cotton t-shirt from the Box o’ Shop Wipes.

    Applying the higher power to the inside of sweatpants fabric, whatever that might be:

    Laser Engraved Fabric - sweatpants
    Laser Engraved Fabric – sweatpants

    Both of those were easier to see in the slanting sunlight of a later winter afternoon.

    The best results come from the lowest feasible power applied at the fastest practical speed, with obvious size and complexity limitations.

    I think this will most useful on a removable tag labeling a piece (perhaps cut from a larger pattern), rather than branding the piece itself.

  • Car vs. Mailbox: Replacement Boxes

    Car vs. Mailbox: Replacement Boxes

    Combining a new mailbox with a post and an old mailbox I had on hand, upcycling some scrap wood, then sticking on a few digits and a seasonal decoration found on a walk, should shake loose the mail currently stuck in the USPS delivery system:

    Mailboxes - south view
    Mailboxes – south view

    That’s an Extra Large mailbox, suitable for most packages arriving by USPS, and dwarfing the ordinary mailbox on the north side:

    Mailboxes - north view
    Mailboxes – north view

    The post is just uphill from the utility pole stub formerly supporting the previous mailboxes. Much to my astonishment, my post hole digger got 30 inches down before hitting The Final Rock, deep enough for the task at hand.

    The boxes sit on slabs harvested from an old door and screwed to two layers of Chinese plywood from the laser cutter’s shipping crate, all unpainted / untreated interior-grade (at best) wood cut with a circular saw. My assumption is they’ll last long enough for the purpose and, not having formed a deep emotional bond with them, I won’t feel too bad when the assembly gets pulverized.

    The whole affair sports a rakish tilt toward the street, in the hope of encouraging rainwater to run off, rather than soak in, but I fully expect the untreated plywood to act as a sponge and delaminate / curl / splay in a spectacular & amusing fashion.

    The pale rectangle across the vertical post is a (laser cut!) Chinese plywood plate intended to hold the crossbar together. The vertical and horizontal posts meet in a simple cross lap joint that surely wasn’t intended to support nearly so much weight: reinforcement seems appropriate.

    Next project: sort out the insurance claim …