Pixel 3a Screen Protector FTW!

Despite carrying a glass-fronted gadget in my pocket for most of the past two decades, this is the first time I’ve done this:

Pixel 3a screen protector - as broken
Pixel 3a screen protector – as broken

Turns out you can’t trust a rolling seat on a slightly unlevel surface, as shifting your weight can let the thing roll out from under you with no warning. If you’re taking a picture at the same time, the phone reaches the impact point before your hand: even a nice case with bumpers all around won’t be quite enough protection.

I was tempted to leave it un-fixed as a constant reminder to not do that again, but the broken glass was rough to the touch and interfered with Android’s swipe-upward gestures.

Fortunately, the tempered-glass screen protector absorbed the energy without damage to the actual screen:

Pixel 3a screen protector - sidelit
Pixel 3a screen protector – sidelit

A thin plastic layer holds the protector’s fragments together; I hadn’t known it was a two-layer structure.

Being that type of guy, I had a spare protector in a desk drawer and managed to apply it without trapping any bubbles or fuzz underneath.

Magnetic Base: Last 10% Manufacturing

A magnetic base of unknown provenance and surprising expense when bought new emerged from the back of the workbench:

Erick Magna Holder - side view
Erick Magna Holder – side view

It’s been hiding back there since the first (attempted) use showed it wasn’t a quadruped:

Erick Magna Holder - as-delivered stance
Erick Magna Holder – as-delivered stance

Grabbing the other end in the bench vise and whacking the top of the offending leg with a brass persuader pretty much lined it up. Closer inspection showed a problem with the push-to-detach lever:

Erick Magna Holder - rivet pivot
Erick Magna Holder – rivet pivot

The rivet head and thin washers extend a bit beyond the circular arc, with the rivet holding the leg above whatever it’s supposed to stick to. I think the scarring on the rivet was an attempt to improve the situation, perhaps during a QC adjustment session, that didn’t quite work.

The hole through the leg is a touch under 4 mm and the Big Box o’ Random Small Screws disgorged a 6-32 screw with what might have been a 5/32 inch = 4 mm nominal = 3.8 mm actual shoulder of exactly the right length:

Erick Magna Holder - 6-32 screw clearance
Erick Magna Holder – 6-32 screw clearance

The screw head flange cleared the floor, but wasn’t much of an improvement over the rivet. I eventually chucked it in the lathe and removed the flange & hex-head corners, an improvement you won’t see here.

Even with the frame whacked into alignment, all four feet didn’t contact the surface plate along their entire lengths. Absent a surface grinder, I deployed a big blue Sharpie and the largest file on hand:

Erick Magna Holder - filing base
Erick Magna Holder – filing base

Iterating Sharpie and file eventually knocked off enough of the high spots to make it Good Enough™ for the intended purpose, which is definitely not precision metrology:

Erick Magna Holder - bottom filed
Erick Magna Holder – bottom filed

Those chunky cross-pieces are Old School alnico magnets, which is the only reason a simple lever can pry it off a steel plate.

Now, at least, it can stand on its own four feet.

As Johnny Mnemonic put it: “These days … you have to be pretty technical before you can even aspire to crudeness“.

Pruning Saw Sharpening

As part of a recent homeowner project, I applied a file to dull pruning saw that, as far as I can recall, Came With The House™ and has been untouched for decades:

Pruning Saw sharpening - top view
Pruning Saw sharpening – top view

Yeah, that’s a lot of steel filings; it was really really dull. Notice how they’re neatly lined up toward the blade?

It looks better from the side:

Pruning Saw sharpening - side view
Pruning Saw sharpening – side view

Despite my crude technique, it cuts wood like a hot knife through butter.

Tour Easy: PTT Switch Cleaning

The switch I installed on Mary’s bike a year ago was intended for indoor use only and, without any trace of weather sealing, recently became intermittent. No surprise, as it’s happened before, but, by regarding my vast assortment of little switches as consumables, we get a low-profile / tactile / E-Z push PTT button without forming a deep emotional attachment.

Anyhow, you can see the unsealed square perimeter of the switch actuator:

Tour Easy - PTT button
Tour Easy – PTT button

The light-gray button sits on a post molded into the actuator. Pry the actuator out and the switch dome shows crud worn off the cross-shaped plunger:

Tour Easy - PTT button - dome plate
Tour Easy – PTT button – dome plate

The underside of the dome has a weird golden discoloration that surely wasn’t original:

Tour Easy - PTT button - dome plate discoloration
Tour Easy – PTT button – dome plate discoloration

I have no idea how a liquid (?) could have gotten in there and done that without leaving other traces along the way. The contact bump on the discolored leg had some crud built up around it which responded well to a small screwdriver.

Contrary to what the symmetrical four-legged dome might suggest, only one leg rests on a contact in a corner:

Tour Easy - PTT button - contacts
Tour Easy – PTT button – contacts

So, yes, a bit of dirt / corrosion / mystery juice in a single spot could render the whole thing intermittent.

I removed the obvious crud from the obvious spots, wiped everything down with some Caig DeoxIT, reassembled in reverse order, and it seems to be all good again. Of course, these things only fail on the road, so it’ll take a few rides to verify the fix.

Multimeter Current-sense Resistor

Replacing the battery in an old Craftsman (!) multimeter brought its 10 A current-sense resistor into the light:

Multimeter current resistor - nipped copper wire
Multimeter current resistor – nipped copper wire

Unlike the contemporary AN8008/9 meters, it looks like an ordinary copper wire trimmed to the proper resistance by nipping it with a cutter.

It measures something under 10 mΩ, so I’m sure they adjusted the resistance by applying a known current and watching the meter reading while crunching the wire until the proper value appears.

I may have actually used the 10 A range, but I’d be hard pressed to say when or why, so the resistor is at least as good as it needs to be!

Round Soaker Hose Clamp

An aging round soaker hose sprang a leak large enough to gouge a crater under a tomato plant, so I conjured a short clamp from the longer round hose splints:

Soaker Hose Clamp - round - installed
Soaker Hose Clamp – round – installed

The shiny stuff is the plastic backing on strips of silicone tape intended to prevent the high-pressure water from squirting through the porous 3D printed plastic. The fat drop hanging from the hose shows some leakage around the tape; an occasional drop is perfectly OK.

The leak faces the round side of the bottom half of the clamp, which probably doesn’t make any difference.

I hope the washers occupy enough of the minimal surface to render aluminum backing plates superfluous:

Soaker Hose Clamp - round - kitted
Soaker Hose Clamp – round – kitted

Creating the 3D model required nothing more than shortening the original splint to 30 mm with two screws along each side. While I was at it, I had Slic3r make three clamps to put two in the Garden Dedicated Hydraulic Repair Kit for later use:

Round Soaker Hose Splice - 30mm - Slic3r
Round Soaker Hose Splice – 30mm – Slic3r

Change two lines in the OpenSCAD code and it’s done.

Also: clamps for flat soaker hoses.