Kenmore Progressive Vacuum Tool Adapters: Third Failure
Posted by Ed in Home Ec, Machine Shop, Software on 2018-11-08
The adapter for an old Electrolux crevice tool (not the dust brush) snapped at the usual stress concentration after about three years:
Crevice tool adapter – broken vs PVC pipe
The lower adapter is the new version, made from a length of 1 inch PVC pipe (that’s the ID, kinda-sorta) epoxied into a revised Kenmore adapter fitting.
The original OpenSCAD model provided the taper dimensions:
Electrolux Crevice Tool Adapter – PVC taper doodles
The taper isn’t quite as critical as it seems, because the crevice tool is an ancient molded plastic part, but a smidge over half a degree seemed like a good target.
Start by boring out the pipe ID until it’s Big Enough (or, equally, the walls aren’t Scary Thin) at 28 mm:
Crevice tool adapter – boring PVC
Alas, the mini-lathe’s craptastic compound has 2° graduations:
Minilathe compound angle scale
So I set the angle using a somewhat less craptastic protractor and angle gauge:
Crevice tool adapter – compound angle
The little wedge of daylight near the gauge pivot is the difference between the normal perpendicular-to-the-spindle axis setting and half-a-degree-ish.
Turning PVC produces remarkably tenacious swarf:
Crevice tool adapter – PVC swarf
The gash along the top comes from a utility knife; just pulling the swarf off didn’t work well at all.
The column of figures down the right side of the doodles shows successive approximations to the target angle, mostly achieved by percussive adjustment, eventually converging to about the right taper with the proper dimensions.
Cutting off the finished product with the (newly angled) cutoff bit:
Crevice tool adapter – cutoff
And then It Just Worked™.
The OpenSCAD source code for all the adapters as a GitHub Gist:
Un-bending a Machinist’s Parallel Clamp Jaw
Posted by Ed in Machine Shop on 2018-11-07
A previous owner used a little too much force on this machinist’s parallel clamp:
Bent parallel clamp jaw
It’s been in the bottom of my clamp box forever, so I figured I should either fix it or toss it. Grabbing the butt end in the bench vise and applying some percussive adjustment with a 3 pound hammer straightened it right out:
Parallel clamps in action
Done!
Modifying a 2.5 mm Collet Pen Holder for a 3 mm Diamond Engraver
Posted by Ed in Machine Shop on 2018-11-06
Of course, the diamond engraving points have a 3 mm shaft that doesn’t fit in the 2.5 mm Collet Pen Holder, but making a hole bigger isn’t much of a problem …
Start by drilling out the collet closer nut:
Collet Holder – closer nut drilling
The hole didn’t start out on center and I didn’t improve it in the least. A touch of the lathe bit and a little file work eased off the razor edge around the snout.
The knurled ridges at the top are larger than the threaded body, which requires a shim around the threads to fit them into the lathe chuck. Start by cutting a slightly larger ID brass tube to the length of the threaded section:
Collet Holder – brass shim cutoff
I finally got a Round Tuit and ground opposing angles on the cutoff tool ends, so I can choose which side of the cut goes through first. In this case, the left side cuts cleanly and the scrap end carries the thinned slot into the chip tray.
Grab the tube in a pair of machinist vises and hacksaw a slot:
Collet Holder – brass shim slitting
Apply a nibbler to embiggen the slot enough to leave an opening when it’s squashed around the threads:
Collet Holder – brass shim around threads
Put a nut on the collet threads in an attempt to keep them neatly lined up while drilling:
Collet Holder – collet drilling
Drill the hole to a bit over 3 mm in small steps, because it’s not the most stable setup you’ve ever used. Eventually, the diamond point just slips right in:
Collet Holder – 3 mm scribe test fit
Reassemble in reverse order and It Just Works:
Collet Holder – finished
Now, to scratch up some acrylic!
Cheese Slicer Rebuild
Posted by Ed in Home Ec, Machine Shop on 2018-11-05
The cheese slicer frame looked much better after sandblasting with 220 aluminum oxide grit:
Cheese slicer – sandblasted
The flower bed outside the Basement Laboratory door seems a bit dusty, though.
Slathering it with JB Weld steel-filled epoxy went reasonably well:
Cheese slicer – JB Weld curing
JB Weld is much much more viscous than the clear XTC-3D I used last year and the final coating, while smoother than what you see here, has too many sags and dents to say “good job”. I didn’t bother coating the upper tips, because the epoxy will wear off from my morning KP.
The aluminum roller turned on those bare stainless steel screws in the tray, with the threads chewing into the roller bore. While the epoxy was curing, I drilled out the roller to remove most of the ridges:
Cheese slicer – drilling roller
Cut a pair of stainless screws slightly longer than the old screws, then turn the threads off to make a shaft:
Cheese slicer – screw reshaping
The lathe spindle runs in reverse, so the cutting force tends to tighten the screw in the nuts. The big old South Bend lathe had a screw-on chuck and didn’t really like turning backwards.
The new screws won’t win any beauty prizes, but they get the job done:
Cheese slicer – screw shafts
Turn a Delrin rod to a press fit in the drilled-out roller:
Cheese slicer – turning Delrin bearing
Part it off, repeat, ram them into the roller, then drill to a loose fit around the smooth-ish screw shafts:
Cheese slicer – drilling Delrin bearing
Reassemble in reverse order:
Cheese slicer – rebuilt
Looks downright industrial, it does.
Stipulated: this makes no economic sense, apart the simple fact we appreciate utensils that just work.
Power Over Audio
Posted by Ed in Electronics Workbench, Oddities on 2018-11-04
An obsolete Intuit / Roam Data credit card reader emerged from the heap:
Intuit Roam Data Reader
“Turn up the volume” suggestes where the power comes from:
Intuit Roam Data Reader – plug wiring
They drive a LOUD, probably square-ish, audio signal through both “earphone”channels, rectify and regulate the output, and have plenty of power for the reader. The card data returns through the “mic” as another audio signal; I assume they choose an encoding well-suited for a dab of DSP decoding.
Nowadays, of course, 3.5 mm jacks are obsolete, audio data travels by Bluetooth, and you must keep a myriad of batteries charged at all times.
Everybody Wants to be a Star
Posted by Ed in Oddities, Photography & Images, Software on 2018-11-03
The Wzye Pan camera overlooking the bird feeders attracted the attention of a Downy Woodpecker:
Screenshot_20181029-112307 – Downy Woodpecker at the Pan
The camera sits on a “guest” branch of the house network, fenced off from the rest of the devices, because Pi-Hole showed it relentlessly nattering with its Chinese servers:
Blocked Domains – Wyze iotcplatform
In round numbers, the Pan camera tried to reach those (blocked) iotcplatform domains every 30 seconds around the clock, using a (permitted) google.com lookup to check Internet connectivity. Pi-Hole supplied the latter from its cache and squelched the former, but enough is enough.
I haven’t tested for traffic to hardcoded dotted-quad IP addresses not requiring DNS lookups through the Pi-Hole. Scuttlebutt suggests the camera firmware includes binary blobs from the baseline Xaiomi/Dafang cameras, so there’s no telling what’s going on in there.
The Xiaomi-Dafang Hacks firmware doesn’t phone home to anybody, but requires router port forwarding and a compatible RTSP client on the remote end. Isolating it from the rest of the LAN must suffice until I can work out that mess; I assume the camera has already made my WiFi passwords public knowledge.
Badger Propel Air Fittings: DIY Cork Washers
Posted by Ed in Machine Shop on 2018-11-02
The tiny sandblaster turns out to be a Badger 260 with miniature Propel threaded fittings on the air line:
Badger Propel air fitting – DIY cork washers
Foreseeing a Propel washer getting lost in the confusion, I punched a few from a cork sheet and trimmed them to half-thickness. The little brass hole punch isn’t good for more than a few whacks, but that’s all I needed. My cork is crumblier than theirs, but I got a few decent-looking washers and, with a bit of luck, won’t need any of them.
Maybe I should make a soft gasket from a thin plastic sheet?
Blowback