Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
A three-LED string in the central control panel of the front handlebars has gone dark a year-and-a-half after I replaced all of them. Of course, that’s what I get for using new-old-stock surplus parts, but … the COB LEDs in the nose ring lights are still going strong, so there’s plenty of light where it matters.
The star pattern on the ceiling (lower right) comes from sunlight reflecting off one of the salvaged star quilting rulers. I think the oblong patterns (upper left) come from other rulers.
Having a mild allergy to whatever plant pollen has begun drifting around these days, I’m trying cheap “nasal strips” intended to hold my nose open overnight, which seem less awful than any of the variety of decongestant / allergy relief pills or potions.
However, while the strips have an adhesive layer strong enough to stick overnight to a slightly oily nose, the skin on the bridge of my nose is fragile enough to hurt after peeling the strip off in the morning. As I see it, the strips need adhesive only on their ends, where they pull outward on my nose, because the center part pushes inward on the bridge.
A few minutes with a rotary cutter and scrap fabric produced dozens of small cushions:
Nasal Strip cushion
Quite inadvertently, the blue fabric looks downright medical.
Your mileage will vary, but the exposed adhesive on the ends sticks firmly to the sides of my nose and, with the cloth protecting the bridge, the strip peels off without injury.
Despite converting other scrap fabric into shop wipes, these tiny cushions are unsuited for laser cuttery, as waking up in the middle of the night with even the faintest campfire smell in my nose would be … triggering.
The 4-½ inch diameter semicircle is there because the larger half needed a handle for easier maneuvering. As with workshop clamps, quilters can never have enough rulers, so that curve will come in handy for something.
Unfortunately, I did not mirror-image the layout like this:
Semicircular Ruler – LightBurn layout
Which would make it correct when seen through the acrylic:
Semicircular Ruler – engraving
Given the very specific use case, I begged forgiveness and was not compelled to get it right.
The instructions for the Photo Backdrop frame (upon which we hang Mary’s quilts for photos) suggest the crossbar fits on like this:
Photo Backdrop – OEM crossbar installation
The slot in the bottom is wider than the M10 stud, so the crossbar tends to flop around while assembling it overhead. I immediately replaced the wingnut with a chunky knob for better griptitude, but was never happy with how poorly the whole thing fit together.
This is dramatically better:
Photo Backdrop – fitting installed
The crossbar is upside-down from the OEM instructions, but the bottom of the gray plug holds the tube firmly to the tripod while the nut seats firmly on the plug’s flat top:
Photo Backdrop – fitting top view
A snippet of 3M 300LSE adhesive sheet holds the plug in place, so that’s one less thing to fiddle with on each end.
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The original needle bar orientation for Mary’s Handiquilter HQ Sixteen put the needle clamp screw (a black-oxide socket head cap screw with the end flattened) about 45° from the rear of the needle bar:
HQ Sixteen – original needle foot orientation
The hex driver passes through the sight hole letting you verify the needle is inserted all the way into the holder before tightening the screw.
It turns out needles fitting the HQ Sixteen come in two varieties, both with nominal 2.0 mm shanks. Mary’s stock has slightly different and entirely consistent diameters around their eyeballometric typical value:
Round shank = 1.94 mm (-0.00 / +0.02 mm)
Flatted shank = 2.04 mm (-0.02 / +0.04 mm)
The round shank needles fit easily into the needle holder, but most of the flatted needles simply would not go in. The difference felt like a burr somewhere inside the bore, rather than a uniformly too-small bore: a burr is easy to imagine around the threaded hole for the lock screw.
Orienting a round-shank needle is exceedingly fiddly, because the groove above the thread hole must be aligned exactly to the front of the needle bar to mesh properly with the bobbin mechanism, but snugging the screw invariably rotates the shank.
While you might think the locking screw would properly orient flatted-shank needles by tightening on the flat, you would be wrong. The flat is at the back of the machine when the groove and hole are properly oriented, which means the locking screw bears on the rounded part of the needle, right at the edge of the flat. Mary was generally unable to use even the few flatted needles that fit into the needle bar, because tightening the screw tended to grab the flat, rotate the needle, and lock it firmly in the wrong orientation.
It is worth nothing that all of the other machines around here have locking screws arranged exactly as you’d expect: tightening the screw onto the shaft flat correctly aligns the needle with zero fiddling.
Pictures of various HQ Sixteen machines found on the InterWebs show their needle bar and locking screw can be oriented anywhere from nearly in front to entirely in the back, suggesting:
Whoever aligns those machines doesn’t care about needle orientation
Everybody uses round-shank needles
Anybody using flatted-shank needles is an outlier
I suggested rotating the needle bar to put the screw in back and, if possible, remove the burr inside the bore. After considerable discussion, my plan was approved.
The needle bar slides vertically in a machined block, driven by a link attached to the machine’s main shaft:
HQ Sixteen Handi-feet conversion – foot rod clamp
The surface of the needle rod has a yellow / amber color from the slick coating that must not be disturbed, to the extent the maintenance instructions require a plastic-lined clamp for adjustments.
The vertical position of the needle rod in the clamp determines the “timing” of the needle with respect to the hook on the whirling bobbin case where the magic happens. Setting the timing requires a Special Service Tool that I do not have and likely never will, so the vertical position must not change while rotating the rod in the clamp.
So, we begin.
Removing the machine cover requires removing the Control Pod electronics box with all its cables to get access to the last screw, so this is a nontrivial operation.
Position the shaft at Bottom Dead Center, then measure the distance from the ruler foot to the needle plate:
HQ Sixteen – Ruler foot clearance
The correct distance is 0.5 mm and the taper gauge shows it at 0.6 mm, but all I need here is putting it back at the same height after I remove the foot.
Position the shaft exactly at Top Dead Center (as shown in the second picture), then stack gage blocks under the needle bar as shown in the top picture. For reference, the gauge block set showing which blocks went into that stack:
HQ Sixteen – gage blocks used
Although I didn’t need the absolute measurement, it’s 0.551 inch = 0.300 + 0.150 + 0.101 inch = 13.995 mm. It’s less than 0.552 inch = 14.021; I decided fiddling with the fourth decimal place would be counterproductive.
With the needle bar held at that height, stick a screwdriver through the hole intended for this purpose and loosen the clamp screw:
HQ Sixteen – needle bar clamp
Yes, the hole is slightly misaligned with the screw, presumably because aligning it properly would put the hole too close to the edge of the frame casting for comfortable drilling. You could make this adjustment without removing the cover, but I’m not that type of guy.
Rotate the needle bar to put the locking screw exactly at the back, verify the bottom of the bar rests on the gauge blocks, tighten the clamp screw, and verify the bottom of the bar rests on the gauge blocks:
HQ Sixteen – needle bar reoriented
Again, the hex driver shows the observation hole orientation.
Acceptance testing requires a practice quilt, but the machine lights up properly and moves smoothly with a needle in place, so it’s pretty close to being correct.
This was one of those jobs requiring about two hours of setup, twenty seconds of adjustment, and half an hour of put-away.
The Industrial Age bobbin winder for Mary’s HQ Sixteen long-arm machine bunched the thread on one end of the bobbin, rather than distributing it in even layers as it should. Tinkering with the thread tension setting being unavailing, I settled in for some debugging.
After filling two bobbins from a spool of the thread Mary uses for practice quilts, I decided I should reuse the thread. Mounting the filled bobbin on a 6 mm horizontal shaft attached to the vertical pin normally locating the spool let the thread pay out in the proper orientation, with a duct-tape lashup holding the shaft in place:
HQ Sixteen bobbin unwind adapter – expedient version
I added the stack of washers to keep the bobbin away from the duct tape after having the tape’s adhesive migrate onto the spinning bobbin.
The thread from the spool or, in my case, a filled bobbin, passes between a pair of tension disks on its way to the bobbin spun by the motor:
HQ Sixteen bobbin winder – thread path
A conical spring presses the tension disks together, with the thread clamped between them:
HQ Sixteen bobbin winder – tension disk overview
The instructions suggest using “the lightest tension possible”, but backing the nut off to hang by its fingernails had no effect. The spring has a bent end passing through the slotted shaft, so rotation of the disks won’t unscrew the nut.
The washer under the mounting screw left slight scars in the black oxide finish on the fixture, presumably from previous attempts to adjust the thing:
HQ Sixteen bobbin winder – tension disk base
The threaded shaft is not exactly parallel to the base, because the upright arm is slightly over-bent, but I think that has no effect on the outcome, because the thread path doesn’t depend on the disk angle.
Because the thread accumulated on the outer side of the bobbin (to the right in that picture), I loosened the mounting screw and shoved the fixture all the way to the left. That should, if anything, bias the thread accumulation to the other (inner) side of the bobbin.
As it turned out, relocating the tension disks caused the thread to distribute evenly across the bobbin, with only occasional hesitations and no significant accumulations; Mary pronounced the result entirely satisfactory.
The motor dataplate says it runs at 7000 RPM, so the 3/4 inch O-ring drives the 4 inch wheel at about 1300 RPM. This was sufficiently terrifying I immediately set up a triac speed control (intended for a router) to throttle it down, but with the bobbins now filling properly we run the motor at full speed and it fills a bobbin in 23 seconds flat.
After we filled half a dozen bobbins with blue thread for the quilt project, I conjured an adapter from the vasty digital deep for a snippet of 6 mm rod with a D-shaped end:
Bobbin Unwind Adapter – solid model – show
The adapter builds on one leg, with a brim for stability:
HQ Sixteen bobbin unwind adapter – on platform
And looks like it belongs there:
HQ Sixteen bobbin unwind adapter – installed
It’s now in the box of HQ Sixteen bobbins, where we both hope it will remain undisturbed forevermore.
Although the vertical pin locating the spools (and holding the adapter) is nominally 6 mm, burrs in the chrome plating prevented the bobbin’s 6 mm bore from sliding over it. In retrospect, that prevented me from just dropping the bobbin on the pin and unwinding the thread over the side of the bobbin, which likely avoided some serious-to-lethal thread tangles.
After all that debugging, I had several bobbins full of well-worn thread, so:
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So the engraved ring on the two in the front row carries a cheerful Sharpie color to make them stand out. I wanted to use fluorescent acrylic, but I don’t have any 4 mm sheets and stacking a pair of 3 mm sheets → 6 mm will be too thick for the pencil tip.
What looks like dirt on the red guide comes from internal reflections or the lack thereof: it’s perfectly transparent in person, honest.
The Smell of Molten Projects in the Morning 