Kenmore Progressive Vacuum Tool Adapters: Third Failure

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

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

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

Crevice tool adapter – boring PVC

Alas, the mini-lathe’s craptastic compound has 2° graduations:

Minilathe compound angle scale

Minilathe compound angle scale

So I set the angle using a somewhat less craptastic protractor and angle gauge:

Crevice tool adapter - compound angle

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

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

Crevice tool adapter – cutoff

And then It Just Worked™.

The OpenSCAD source code for all the adapters as a GitHub Gist:


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Un-bending a Machinist’s Parallel Clamp Jaw

A previous owner used a little too much force on this machinist’s parallel clamp:

Bent parallel clamp jaw

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

Parallel clamps in action



Modifying a 2.5 mm Collet Pen Holder for a 3 mm Diamond Engraver

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

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

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

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

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

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

Collet Holder – 3 mm scribe test fit

Reassemble in reverse order and It Just Works:

Collet Holder - finished

Collet Holder – finished

Now, to scratch up some acrylic!

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Cheese Slicer Rebuild

The cheese slicer frame looked much better after sandblasting with 220 aluminum oxide grit:

Cheese slicer - sandblasted

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

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

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

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

Cheese slicer – screw shafts

Turn a Delrin rod to a press fit in the drilled-out roller:

Cheese slicer - turning Delrin bearing

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

Cheese slicer – drilling Delrin bearing

Reassemble in reverse order:

Cheese slicer - rebuilt

Cheese slicer – rebuilt

Looks downright industrial, it does.

Stipulated: this makes no economic sense, apart the simple fact we appreciate utensils that just work.

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Power Over Audio

An obsolete Intuit / Roam Data credit card reader emerged from the heap:

Intuit Roam Data Reader

Intuit Roam Data Reader

“Turn up the volume” suggestes where the power comes from:

Intuit Roam Data Reader - plug wiring

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

The Wzye Pan camera overlooking the bird feeders attracted the attention of a Downy Woodpecker:


Screenshot_20181029-112307 - Downy Woodpecker at the Pan

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

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) 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.

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Badger Propel Air Fittings: DIY Cork Washers

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

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?