Kenmore Model 158: Foot Pedal Pivots
Posted by Ed in Home Ec, Machine Shop on 2019-08-11
I got an email asking how the Kenmore Model 158 sewing machine’s foot pedal pivots worked. The notes on rebuilding the carbon disk rheostat and conjuring a Hall effect sensor show the innards, but here’s what you need to know to get there.
The pedal has a pair of pivots on the side closest to your foot, held in place with a small screw inside the two feet:
The screw fits into a notch in the unthreaded pin inserted from the side:
And that’s all there is to it!
Now, as happened to my correspondent, the pin can go missing, perhaps after the screw worked loose. Worst case, you’re looking at replacing both parts.
Being made in Japan (as ours were), the pedal has metric sizes: the unthreaded pin is 4 mm in diameter and 18 mm long and the setscrew has an M4×0.7 thread. You could replace the pin with an 18 mm (down to maybe 15 mm) long M4 screw. The threads would make a gritty pivot, but better than no pivot at all.
Better to get a longer M4 screw with an unthreaded section near the head, hacksaw it to the proper length, file to tidy up the cut end, maybe file a notch for the setscrew, and pop it in place. For tidiness, file off the slot / Philips / hex socket to eliminate the temptation to turn it out.
Worst case, a pair of plain old USA-ian 6-32 screws 3/4 inch long would make a sloppy fit. Don’t tell anybody I said so; that’d be barely better than nothin’ at all in there.
Lowe’s claims to have M4×0.7 setscrews (with a hex socket, not a slot) to secure the pin.
If my experience around here is any guide, however, Lowe’s / Home Depot / Walmart may claim to have metric hardware in stock, but the only way to know is to actually go there and rummage around in the specialty hardware section, inside the big steel cabinet with slide-out drawers filled with a remarkable disarray of ripped-open bags and misfiled parts.
Good hunting …
Mystery Knife / Chisel
Posted by Ed in Machine Shop, Oddities, Recumbent Bicycling on 2019-08-10
I recovered a tool from an intersection during the homeward leg of a bike ride:
The scabbard is a bit the worse for having been run over by traffic, but the knife is still in good shape.
The back of the blade has been well and truly mushroomed:
The blade edge doesn’t have nearly as much damage as you’d (well, I’d) expect from all the hammering on the back and sides:
The molded handle suggests it’s a commercial product, but it has no branding, no maker’s mark, no identification of any kind.
Google Image Search returns useless views of tail lights and rifles. Here, try it for yourself:
I have no idea what it’s used for.
Do you?
[Update: It’s a Bell System Cable-Sheath Splitting Knife, made by Klein Tools. More details in the comments … ]
Xiaomi-Dafang Hacks: FTP Server for Camera Files
Posted by Ed in Home Ec, Photography & Images, Software on 2019-08-09
Since the PiHole runs all the time, it now hosts an FTP server to stash snapshots from the cameras onto a 64 GB USB stick. I installed ProFTPD, which Just Worked with a few configuration tweaks:
UseIPv6 off
ServerName "PiHole"
DefaultRoot /mnt/cameras
RequireValidShell offThe cameras use the BusyBox ftpput command to stash their images (with the hostname prepended), which requires a few changes to motion.conf in the cameras:
ftp_snapshot=true
ftp_host="192.168.1.2"
ftp_port=21
ftp_username=$(/bin/hostname)
ftp_password="make up your own"
ftp_stills_dir=$(/bin/hostname)The last line uses a separate directory for each camera, although they quickly ran into the FAT32 limit of 64 K files per directory; reformatting the USB stick with an ext3 filesystem solved that problem.
Fortunately, nothing much ever happens around here …
NuTone 8663RP Bathroom Vent Fan: Effective Repair
Posted by Ed in Home Ec, Machine Shop on 2019-08-08
My high hopes for the UHMW bushing supporting the impeller lasted the better part of a day, because direct contact between the impeller and the motor bearing produced an absurdly loud and slowly pulsating rumble:
My hope that the UHMW would wear into a quieter configuration lasted a week …
Back in the Basement Shop, some free-air tinkering showed the impeller produced enough suction to pull itself downward along the shaft and jam itself firmly against the motor frame. My initial thought of putting a lock ring around the shaft to support the impeller turned out to be absolutely right.
So, make a small ring:
With a 4-40 setscrew in its side, perched atop the impeller for scale:
It just barely fits between the impeller and the motor frame:
This reduced the noise, but the hole in the impeller has worn enough to let it rotate on the shaft and the rumble continued unabated. The correct way to fix this evidently requires a mount clamped to both the shaft and the impeller.
Fast-forward a day …
A careful look at the impeller shows seven radial ribs, probably to reduce the likelihood of harmonic vibrations. After a bit of dithering, I decided not to worry about an off-balance layout, so the screws sit on a 9 mm radius at ±102.9° = 2 × 360°/7 from a screw directly across from the setscrew in another slice from the 1 inch aluminum rod:
Centered on the disk and using LinuxCNC’s polar notation, the hole positions are:
G0 @9.0 ^-90
G0 @9.0 ^[-90+102.9]
G0 @9.0 ^[-90-102.9]As usual, I jogged the drill downward while slobbering cutting fluid. I loves me some good manual CNC action.
Put the mount on a 1/4 inch tube, stick it into the impeller, and transfer-punch the screw holes:
Apparently, some years ago I’d cut three screws to just about exactly the correct length:
I knew I kept them around for some good reason!
The 9 mm radius just barely fits the screw heads between the ribs:
Some Dremel cutoff wheel action extended the motor shaft flat to let the setscrew rest on the bottom end:
Then it all fit together:
The fan now emits a constant whoosh, rather than a pulsating rumble, minus all the annoying overtones. It could be quieter, but it never was, so we can declare victory and move on.
Dropping fifty bucks on a replacement fan + impeller unit would might also solve the problem, but it just seems wrong to throw all that hardware in the trash.
And, despite making two passes at the problem before coming up with a workable solution, I think that’s the only way (for me, anyhow) to get from “not working” to “good as it ever was”, given that I didn’t quite understand the whole problem or believe the solution at the start.
But it should be painfully obvious why I don’t do Repair Cafe gigs …
Logitech “Quickcam for Notebooks Deluxe” USB Camera Disassembly
Posted by Ed in Electronics Workbench, Machine Shop, Photography & Images on 2019-08-07
My collection of old USB cameras emitted a Logitech Quickcam for Notebooks Deluxe, with a tag giving a cryptic M/N of V-UGB35. Given Logitech’s penchant for overlapping names, its USB identifiers may be more useful for positive ID:
ID 046d:08d8 Logitech, Inc. QuickCam for Notebook DeluxeIt works fine as a simple V4L camera and its 640×480 optical resolution may suffice for simple purposes, even if it’s not up to contemporary community standards.
The key disassembly step turned out to be simply pulling the pivoting base off, then recovering an errant spring clip from the Laboratory Floor:
The clips have a beveled side and fit into their recesses in only one orientation; there’s no need for brute force.
Removing the two obvious case screws reveals the innards:
Three more screws secure the PCB:
The ribbed focus knob around the lens makes it more useful than a nominally fixed-focus camera.
Reassembly is in reverse order.
I miss having obvious case screws …
Beware the Domain Squatters
Posted by Ed in Administrivia, Software on 2019-08-06
A squatter has taken over a defunct domain at the far end of a link buried somewhere in the 3800 posts you find here. In place of the useful page I saw, you’ll see this stylin’ popover:
The “standard security check” is a nice touch, although you should keep in mind the Dilbert cartoon about unexpected side effects.
The actual URL, which I will not make clickable, includes the domain ffgetsplendidapps, which tells you just about everything you need to know about what’s going on.
Because they’re squatting, “continue directly to your destination” means being dumped into a Google search after they’ve meddled with your browser & system configuration. Clicking the inconspicuous × in the upper right closes the popover and dumps you into the search, perhaps before doing anything.
I have no good (i.e., automated) way to find broken links and, as far as I know, there is no way to automatically detect domain squatting, so you’re on your own.
Trust, but verify!
Warm-White LED Strip: FAIL
Posted by Ed in Electronics Workbench, Oddities on 2019-08-05
The roll of warm-white LEDs I used for the first sewing machine lights has evidently aged out:
They’ve been wrapped on their original roll, tucked in an antistatic bag, for the last five years, so it’s not as if they’ve been constantly abused.
All the cool-white LEDs on an adjacent roll in the same bag still work perfectly, so you’re looking at inherent vice.
I harvested the three longest functional sections and dumped the remainder in the electronics recycling box.
COB LEDs provide much more light, if only because they run at higher power densities, and seem to be much better cost-performers:
Admittedly, I haven’t looked at the RGB LED strips in a while, either.
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