Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
A low-end audio power amp destined for a pair of ancient-yet-still-serviceable speakers arrived, but attempting to poke wires through the side holes of the banana jacks showed they were oriented in random directions. Back in the day, banana jacks had D-shaped shafts fitted into D-shaped panel holes, but those days are gone.
A few minutes with screwdriver, wrench, and (tiny) punch sufficed to line up the holes for E-Z poking:
Fosi audio amp – jack alignment
Despite the new convenience, I decided to solder banana plugs to the speaker wires, leading to the discovery my few remaining plugs came from the very bottom of the usability barrel:
Cheap banana plug – solder side
I have no idea how one might affix a wire to that blank stub, but poking a small center drill into the brass lump produces an easily solderable recess:
Cheap banana plug – center drilled
Dab with flux, tin, insert wire, add solder, repeat with all four plugs, and I’m set with a boomin’ system.
The entire metal base shell unscrewed from the plastic housing and twisted off the lead from what looks like a PTC fuse in series with the center contact; the cute little pigtail effect suggests I’ve wrecked the epoxy-to-wire seal.
It had a five year warranty which, alas, expired three years ago. This style of bulb has fallen out of favor, so I may as well get some Quality Shop Time out of it.
I don’t know how the factory machinery attached the lead to the contact button, but I’m going to go primal on it with some solder. The trick will be soldering it after assembly, so the first step is to drill through the middle of the button.
Grab it nose-down in the Sherline’s three-jaw chuck, flip it over, grab the chuck in the drill press vise, line it up, center-drill the button, then drill right through that sucker:
LED Bulb – base drilling setup
Of course, the contact came loose from the base, because I pretty much drilled right through the rivet flange holding it in place:
LED Bulb – removed center contact
Nothing a dab of epoxy can’t fix, though. I scuffed up the outside of the contact to remove the nickel (?) plating and expose the underlying brass to improve its solderability.
After the epoxy cured, align wire with hole, screw the base onto the lamp shell, and it’s ready for soldering:
LED Bulb – base ready for solder
The hole is way too large for the wire, but I wasn’t about to wreck a tiny drill on what might have been a weld nugget. In any event, the bigger the blob, the better the job:
LED Bulb – soldered base
Just like light bulb bases used to look, back in the day.
With a bit of luck, it’ll sit in that socket for another seven years.
Because I live in the future and had solved this problem in the past, eight hours of print time produced a second shade:
Torchiere Lamp Shade 2 – on platform
I sliced the same STL file with PrusaSlicer to get G-Code incorporating whatever configuration changes I’ve made to the M2 over the years and include any slicing algorithm improvements; the OpenSCAD code remains unchanged.
The as-printed shade had pretty much the same crystalline aspect as the first one:
Torchiere Lamp Shade 2 – no epoxy
Smoothing a layer of white-tinted epoxy over the interior while spinning it slowly in the mini-lathe calmed it down enough for our simple needs, although the picture I tried to take didn’t show much difference.
While pondering a project requiring a slitting saw, I discovered the clamp on the dial test indicator magnetic mount I’d picked up a while ago didn’t quite fit the 5/32 inch = 4 mm stem on the indicator. The clamp ring is obviously punched from sheet, then formed into its final shape, as the holes are somewhat un-round. Running the proper drill through the holes removed a minute sliver of steel:
Dial test indicator mount – redrilling
And then it fit just fine:
Dial test indicator mount – in use
Although it looks like I’m in the process of sawing the ball off the indicator, I’m really measuring the runout, which turned out to be maybe 5 mils = 0.13 mm. The blade is likely too small for what I’m thinking of using it for, so the pondering continues.
The two bigger holes in the clamp fit the equally standard 3/8 inch = 9.5 mm stems just fine, so it’s just another one of those tools where I get to finish the last few percent of their manufacturing.
You’re supposed to secure the photo backdrop’s top crossbar to the uprights by fiddling with a wingnut, which you must do while reaching over your head. Emart apparently realized this operation was fraught with peril, because the package contains four wingnuts. After setting it up once, I replaced the wingnuts with finger-friendly knobs containing acorn nuts:
The knobs come from Thingiverse, although the OpenSCAD program required a bit of rework to make it compatible with the current version. Fiddling around with the Customizer parameters produced a Good Enough knob:
M10x1.5 Acorn Nut knob – solid model
I pulled the acorn nut into the knob using the upright pole hardware to keep it aligned. Spin the wingnut on the stud “backwards”, add the washer, push the nut slightly into the knob to get it started, then thread it onto the stud:
Photo Backdrop – knob nut seating – 1
Turn the knob to pull the nut inward until the stud hits the inside of the nut:
Photo Backdrop – knob nut seating – 2
Unthread the nut a bit, run the wingnut out to meet the bottom of the knob, and repeat the operation until the nut bottoms out inside the knob:
Photo Backdrop – knob nut seated
Toss the wingnuts into the Warehouse Wing against later use.
Bonus project: on the other end of the upright, you’ll find it impossible to actually lock the leg carrier against the pole:
Photo Backdrop – tripod leg lock
The plastic fitting is … generously … sized around the 25 mm OD upright pole and requires more compression than I could produce with my puny fingers. It turns out the 18 mm OD leg tube exactly fills the space available inside the fitting, so you (well, I) must squash the steel tube in order to close the fitting on the pole.
Remove the wingnut + screw to free the end of the leg, stick an inch of the leg into the bench vise’s soft jaws, and mash gently to about 16 mm across the holes; it’ll expand slightly in the other direction. Reassemble in reverse order and discover the thumbscrew now squeezes the fitting exactly as it should.
There might be more finishing to do when we actually hang a quilt from the stand, but at least it’s now usable.
After turning the key and dialing the correct combination, the unlocking handle on the basement safe refused to move. Applying the dictum “If brute force isn’t working, you’re not using enough of it”, we eventually persuaded the handle downward and the door swung open. Before applying the dictum “If it doesn’t move and should, use WD-40 [*]”, I had to remove the trim cover from the interior side of the door to gain access to the lockwork.
Start by pressing the two latches inside the small circular holes in the hinge side of the trim cover:
Sentry FireSafe Door – first latches
Pull the trim over the slightly chamfered bolts, taking advantage of the fact the bottom pulls out more easily than the top, then pry it upward off the latch in the middle of the top:
Sentry FireSafe Door – top latch
The latches along the other side yield when you bend the trim sufficiently far from the door while applying the Designated Prydriver near the faint mold markings visible around the edge:
Sentry FireSafe Door – last latches
With the trim removed, you can see fancier safes in this line have two additional bolts engaging the top and bottom of the door frame. The rectangular block on the bottom of the hinge side might be for the batteries required by the spendy electronic lock version.
The problem turned out to be a lack of lubrication in the door-closed interlock that prevents you from relocking the bolts and wrecking the mechanism when you try to close the door with the bolts extended:
Sentry FireSafe Door – bolt interlock
A dab of silicone lube on all those sliding interfaces restored the interlock’s good humor.
The bolts had always rubbed just a bit on the trim cover, so I ovalized the offending side of the holes with an Xacto knife.
Slamming the trim firmly back on the door reset the latches, cycling the lockwork resynchronized the interlock, and the safe once again works just like it should.
[*] WD-40 is not the appropriate lube for the lockwork inside a safe, but the dictum aims you in the right direction.
The torchiere floor lamp in the sewing room suffered a catastrophic failure:
Floor lamp – failed plastic base shell
Contrary to what you might think from seeing the shattered plastic base, we didn’t use the lamp as a club or battering ram. Apparently the designer expected the thin plastic surrounding the hole to withstand all the torque produced by the long pole against the cheap concrete / mortar / grout / whatever lump in the base. As we can recall, this lamp came to us from either a yard sale or a roadside debris harvest, so I suppose the hardware outlasted any reasonable expectation.
The Basement Laboratory Warehouse disgorged the pole and base from a similar lamp, albeit sporting black paint and a smaller rod connecting its pole to its somewhat larger weight. Not being too fussy about decor, I embiggened the hole in the black base to fit the white lamp’s threaded rod:
Floor lamp – enlarging replacement base
The dust on the base shows why you shouldn’t stand motionless in the Basement Laboratory for very long.
The alert reader will have noted the cord passing through a strain relief grommet in the white base. Rather than dismantle the entire lamp, I just cut the cord, ran it through the new base weight, reinstalled the washer + nut, then crimped on a pair of solderless connectors:
Floor lamp – cord splice
The new base doesn’t offer much in the way of attachment points, so I added a cable tie to keep the strain off the connectors:
Floor lamp – cord strain relief
A strip of genuine 3M duct tape with double-thick adhesive now traps the cord inside that small channel and, given that the lamps spends most of its time standing quietly in a corner, the cord should be fine for long enough.
The Smell of Molten Projects in the Morning 