Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
After few days in the Drive Blue Streak wheelchair, I finally lubricated the foot rest pivots:
Drive wheelchair foot rest lubrication
The complex molded rests gripped their metal tubes so tightly as be nearly immovable, but one drop of Kroil at the four obvious spots let them turn much more easily.
The flange overlapping the upright tube along the bottom of the picture hits the short protrusion and holds the rest parallel to the floor. A screw at the plastic cap near the top keeps the rests from working their way too far from the upright tube.
I can make it to the Basement Shop™ and back, paying careful attention to detail.
Mary wanted a Ruler Foot (a.k.a. Handi Feet Sure Foot) on her Handi Quilter HQ Sixteen sewing machine, which required removing the original foot, installing the Handi Feet Conversion Kit, then adjusting the foot height above the needle plate:
The Conversion Kit instructions repeatedly recommend hauling the machine to your local Handi Quilter authorized dealer / repair center, which would be an hour’s drive away. Suffice it to say I’m both authorized by a suitable authority and a dab hand with a hex wrench: I can do this thing.
The original foot is a welded assembly with an M5×0.8 screw thread matching the leftmost (darker) rod on the machine:
HQ Sixteen Handi-feet conversion – original foot
It’s sitting atop the label of the Sure Foot kit with a picture of the ruler foot.
Although the instructions suggest you can install the conversion kit without removing the machine cover, I wanted to see what was going on in there and verify everything fit properly:
HQ Sixteen Handi-feet conversion – foot rod clamp
As above, the foot / adapter screws into the left rod, with the rectangular aluminum clamp attached to the follower riding the cam near the top of the machine. The rod slides on the greasy pin absorbing the torque from the follower.
I had to loosen the clamp, slide the rod upward, unscrew the original foot, install the adapter, adjust the rod position for the proper 0.5 mm spacing between ruler foot and the needle plate at bottom dead center, then tighten the screw. The disturbed grease above the block reveals I moved the rod upward about 8 mm through that block during the process; it now sits lower, just a few millimeters above where the factory tech assembled it for the original foot.
The top photo shows half a dozen threads between the top of the adapter and the bottom of the jam nut. Without adjusting the rod position in the clamp, the adapter screw threads are the only way to adjust the foot-to-plate space: each full turn moves the foot 0.8 mm. I screwed the adapter completely into the rod, then backed it out three turns to leave enough adjustment for other feet and fabrics.
The machine cover has a hole providing access to the clamp screw, so, in principle, you can stick a hex wrench in there to loosen / tighten the clamp while making fine adjustments in the foot position, all without removing the cover. If one full turn of the adapter doesn’t set the right position, I highly recommend removing the machine cover to see what you’re doing.
We then installed the Ruler Base on the machine, which required removing the preinstalled Medium fuzzy spacer strips, and all’s well that ends well.
Over the past year, the ancient WordPress theme I use for this blog has gradually stopped working, to the extent that some of you cannot enter comments and the GitHub Gists no longer display properly.
The ↓ (“down”) button on one of our lift chairs stopped working, although the ↑ (“up”) button worked fine and, as you’d expect, verifying this problem left the chair in a rather awkward position.
The usual power cycle and unplugging / replugging the control had no effect.
This control is the one I couldn’t pry apart to dim its LEDs, so I tried various combinations of pins until this scribble emerged:
Pride Lift Chair – control pinout doodle
I have no idea of the correct pin numbering, but the scribble looks into the connector pins with the keyway on top:
Pride lift chair control
The more intricate control for the other Pride lift chair has only four pins in its connector, so I couldn’t just swap them to see what happened.
The polarities are for the continuity / resistance test probes.
The takeaway: The two buttons did similar things to two different connector pins, so the control seemed to be working correctly and the fault lies elsewhere.
The control sports a USB jack for powering / charging your favorite device and I’m reasonably sure the control has a microcontroller tucked in there for good reason, implying the circuitry is surely more complex than maybe a rectifier bridge and some resistors.
So I shoved the chair into the middle of the room, deployed some test equipment, reconnected the control, plugged the chair power supply into the outlet strip, and … of course both buttons worked perfectly.
Soooo the chair is back in place and we’ll see what happens next.
Speaking of Heisenbugs, the HQ Sixteen continues to work fine, too.
For whatever reason, the Thunar file browser in XFCE does not automagically show thumbnails for webp images. Some searching produced a recipe, although the displayed webp.xml file needs the last two lines to close the tags:
After installing (if that’s not too fancy a term) the horizontal thread spool adapter on the HQ Sixteen, I laser-cut an acrylic disk to keep thread cones centered on the other vertical spool pin:
HQ Sixteen – thread cone base locator – installed
It’s trivial: an 11 mm circle to clear the washer and a 55 mm circle to locate the cone.
However, I cut that disk with a 56 mm OD, because that’s what I measured on half a dozen cones. Come to find out at least some cone bases are juuust slightly oval and they latched onto that disk like they were gonna be best buddies forever.
Rather than cut another acrylic disk, I laser-cut a friction ring from a scrap of stamp-pad rubber and jammed the disk against the chuck with a live center:
HQ Sixteen – thread cone base locator – turning
A few minutes of sissy cuts made the disk nicely round and concentric with the inner hole, with a little file work knocking the edges off the rim.
The Smell of Molten Projects in the Morning 