Machine Shop – Page 163 – The Smell of Molten Projects in the Morning

Sony NP-FM50 Battery Disassembly

Having won an eBay action for a known-dead Sony DSC-F717 at $0.99 (plus $15 shipping, the seller being no fool), I now have a possibly salvageable camera, a Genuine Sony AC supply, and two more NP-FM50 batteries for about the price of any one of the components.

One battery arrived stone-cold dead, suggesting the camera had been put away with the battery installed for a very long time and they died companionably. The camera still charges a (good) battery, even though it doesn’t turn on, and perusing the schematics suggests checking the power switch, because it’s always the switch contacts. That’s for another day, though.

For the record, the battery status:

NP-FM50 - 2019-03-30 — NP-FM50 – 2019-03-30

The red and green traces come from the two batteries I’ve been cycling through the camera since, um, 2003, so they’re getting on in years and correspondingly low in capacity.

The fourth battery (2019 D, the date showing when it arrived, not its manufacturing date) went from “fully charged” to “dead” in about three seconds with a 500 mA load, producing the nearly invisible purple trace dropping straight down along the Y axis.

Sawing the dead battery case around its welded joint at a depth of 0.75 mm, then prying with a small chisel, exposed the contents without histrionics:

Sony NP-FM50 battery - cell label — Sony NP-FM50 battery – cell label

Now, there’s a name to conjure with. Turns out Sony sold off its Fukushima battery business a while back, so these must be collectibles. Who knew?

The lower cell is lifeless, the upper cell may still have some capacity. Three pairs of 18500 lithium cells are on their way, in the expectation of rebuilding the weakest packs.

After desoldering the battery tab on the right from the PCB, it occurred to me I needed pictures:

Sony NP-FM50 battery - PCB exposed — Sony NP-FM50 battery – PCB exposed

Yeah, that’s a nasty melted spot on the case, due to inept solder-wickage.

Unsoldering the three tabs closest to the case releases the cells + PCB from confinement:

Sony NP-FM50 battery - PCB overview — Sony NP-FM50 battery – PCB overview

I’m still bemused by battery packs with a microcontroller, even though all lithium packs require serious charge controllers. At least this is an Atmel 8-bitter, rather than 32-bit ARM hotness with, yo, WiFi.

The cells have shaped tabs which will require some gimmicking to reproduce:

Sony NP-FM50 battery - cell tabs — Sony NP-FM50 battery – cell tabs

Now, if only I could reboot the camera …

2019-04-08

Broken Spoke

On the drive side, of course:

Tour Easy - broken rear spoke — Tour Easy – broken rear spoke

I’d noticed some brake drag on our last few rides, but forgot to check until I saw the rim wobble while extracting images from the rear camera.

It’s a lot easier to fix in the Basement Shop than on the road. After nigh onto a decade since replacing the last broken spoke, perhaps this is a harbinger of doom to come.

Memo to Self: spoke tension is now 20-ish on the drive side, 15-ish on the left.

2019-04-06

Seam Ripper Cover

The cover for Mary’s favorite seam ripper cracked long ago, has been repaired several times, and now needs a replacement:

The first pass (at the top) matched the interior and exterior shapes, but was entirely too rigid. Unlike the Clover seam ripper, the handle has too much taper for a thick-walled piece of plastic.

The flexy thinwall cover on the ripper comes from a model of the interior shape:

Seam Ripper Cover - handle model — Seam Ripper Cover – handle model

It’s not conspicuously tapered, but OpenSCAD’s perspective view makes the taper hard to see. The wedge on top helps the slicer bridge the opening; it’s not perfect, just close enough to work.

A similar model of the outer surface is one thread width wider on all sides, so subtracting the handle model from the interior produces a single-thread shell with a wedge-shaped interior invisible in this Slic3r preview:

Seam Ripper Cover - exterior - Slic3r preview — Seam Ripper Cover – exterior – Slic3r preview

The brim around the bottom improves platform griptivity. The rounded top (because pretty) precludes building it upside-down, but if you could tolerate a square-ish top, that’s the way to go.

Both models consist of hulls around eight strategically placed spheres, with the wedge on the top of the handle due to the intersection of the hull and a suitable cube. This view shows the situation without the hull:

Seam Ripper Cover - handle model - cube intersection — Seam Ripper Cover – handle model – cube intersection

The spheres overlap, with the top set barely distinguishable, to produce the proper taper. I measured the handle and cover’s wall thicknesses, then guesstimated the cover’s interior dimensions from its outer size.

The handle’s spheres have a radius matching its curvature. The cover’s spheres have a radius exactly one thread width larger, so the difference produces the one-thread-wide shell.

Came out pretty nicely, if I do say so myself: the cover seats fully with an easy push-on fit and stays firmly in place. Best of all, should it get lost (despite the retina-burn orange PETG plastic), I can make another with nearly zero effort.

The Basement Laboratory remains winter-cool, so I taped a paper shield over the platform as insulation from the fan cooling the PETG:

Seam Ripper Cover - platform insulation — Seam Ripper Cover – platform insulation

The shield goes on after the nozzle finishes the first layer. The masking tape adhesive turned into loathesome goo and required acetone to get it off the platform; fortunately, the borosilicate glass didn’t mind.

The OpenSCAD source code as a GitHub Gist:

	// Cover for old seam ripper
	// Ed Nisley – KE4ZNU
	// 2019-03

	/* [Layout Options] */

	Layout = "Build"; // [Show,Build]

	Part = "Handle"; // [Handle,CoverSolid,Cover]

	/* [Extrusion Parameters] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions


	/* [Dimensions] */

	WallThick = 1*ThreadWidth;

	CapInsideLength = 48.0;

	CornerRadius = 2.0; // handle at base

	Base = [11.0,5.5,0.0]; // handle at base

	Tip = [8.2,3.7,CapInsideLength]; // inferred at tip

	HandleOC = [Base – 2*[CornerRadius,CornerRadius,0.0],
	Tip – 2*[CornerRadius,CornerRadius,CornerRadius/2]
	];

	NumSides = 234;


	//—–
	// Useful pieces

	// Handle is basically the interior of the cover

	module Handle() {

	intersection() {
	hull()
	for (i=[-1,1], j=[-1,1], k=[0,1])
	translate([iHandleOC[k].x/2,jHandleOC[k].y/2,k*HandleOC[k].z])
	sphere(r=CornerRadius,$fn=NumSides);
	translate([0,0,-CornerRadius/2]) // chop tip for better bridging
	rotate([45,0,0])
	cube([2Base.x,CapInsideLengthsqrt(2),CapInsideLength*sqrt(2)],center=true);
	}
	}

	module CoverSolid() {

	hull()
	for (i=[-1,1], j=[-1,1], k=[0,1])
	translate([iHandleOC[k].x/2,jHandleOC[k].y/2,k*HandleOC[k].z])
	sphere(r=CornerRadius + WallThick,$fn=NumSides);

	}

	module Cover() {

	difference() {
	CoverSolid();
	Handle();
	translate([0,0,-CornerRadius])
	cube(2Base + [0,0,2CornerRadius],center=true);
	}
	}

	//—–
	// Build things

	if (Layout == "Build") {
	Cover();
	}

	if (Layout == "Show")
	if (Part == "Handle")
	Handle();
	else if (Part == "CoverSolid")
	CoverSolid();
	else if (Part == "Cover")
	Cover();

view raw Seam Ripper Cover.scad hosted with ❤ by GitHub

2019-04-05

Desk Lamp Conversion: Photo Light Cold Shoe

Having recently acquired a pair of photo lights and desirous of eliminating some desktop clutter, I decided this ancient incandescent (!) magnifying desk lamp had outlived its usefulness:

Desk Lamp - original magnifiying head — Desk Lamp – original magnifiying head

The styrene plastic shell isn’t quite so yellowed in real life, but it’s close.

Stripping off the frippery reveals the tilt stem on the arm:

Desk Lamp - OEM mount arm — Desk Lamp – OEM mount arm

The photo lights have a tilt-pan mount intended for a camera’s cold (or hot) shoe, so I conjured an adapter from the vasty digital deep:

Photo Light Bracket for Desk Lamp Arm - solid model — Photo Light Bracket for Desk Lamp Arm – solid model

Printing with a brim improved platform griptivity:

Photo Light Bracket for Desk Lamp Arm - Slic3r preview — Photo Light Bracket for Desk Lamp Arm – Slic3r preview

Fortunately, the photo lights aren’t very heavy and shouldn’t apply too much stress to the layers across the joint between the stem and the cold shoe. Enlarging the stem perpendicular to the shoe probably didn’t make much difference, but it was easy enough.

Of course, you (well, I) always forget a detail in the first solid model, so I had to mill recesses around the screw hole to clear the centering bosses in the metal arm plates:

Photo Lamp - bracket recess milling — Photo Lamp – bracket recess milling

Which let it fit perfectly into the arm:

Desk Lamp - photo lamp mount installed — Desk Lamp – photo lamp mount installed

The grody threads on the upper surface around the end of the slot came from poor bridging across a hexagon, so the new version has a simple and tity flat end. The slot is mostly invisible with the tilt-pan adapter in place, anyway.

There being no need for a quick-disconnect fitting, a 1/4-20 button head screw locks the adapter in place:

Photo Lamp - screw detail — Photo Lamp – screw detail

I stripped the line cord from inside the arm struts and zip-tied the photo lamp’s wall wart cable to the outside:

Photo Lamp - installed — Photo Lamp – installed

And then It Just Works™:

Photo Lamp - test image — Photo Lamp – test image

The lens and its retaining clips now live in the Big Box o’ Optical parts, where it may come in handy some day.

The OpenSCAD source code as a GitHub Gist:

	// Photo light mount for desk lamp arm
	// Ed Nisley – KE4ZNU
	// 2019-03

	/* [Layout Options] */

	Layout = "Build"; // [Show,Build]

	Part = "Mount"; // [LampArm,ShoeSocket,Mount]

	/* [Extrusion Parameters] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	/* [Dimensions] */

	FrictionDisk = [4.0,16.5,11.0]; // squashed inside desk lamp arm frame
	Divots = [4.0,9.5,0.75]; // recesses for frame alignment bumps
	ArmLength = 30.0; // attached to disk

	ShoeWheelOD = 32.0; // lock wheel on photo lamp
	ShoeBase = [18.5,18.5,2.0] + [HoleWindage,HoleWindage,2*ThreadWidth]; // square base on photo lamp gimbal
	ShoeStem = [6.3,12.0,1.5]; // top slide clearance, ID = 1/4 inch screw
	ShoeBlock = [ShoeWheelOD,ShoeWheelOD,2*(ShoeBase.z + ShoeStem.z)]; // overall shoe block

	NumSides = 3*4;

	//—–
	// Useful routines

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	module PolyCyl(Dia,Height,ForceSides=0,Center=false) { // based on nophead's polyholes

	Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

	FixDia = Dia / cos(180/Sides);

	cylinder(r=(FixDia + HoleWindage)/2,h=Height,$fn=Sides,center=Center);
	}


	//—–
	// Various Parts

	// Arm captured in disk lamp

	module LampArm() {

	difference() {
	union() {
	cylinder(d=FrictionDisk[OD],h=FrictionDisk[LENGTH],$fn=NumSides,center=true);
	hull()
	for (j=[-1,1])
	translate([0,j*(FrictionDisk[OD]/2 – FrictionDisk[LENGTH]/2),0]) {
	rotate([0,90,0]) rotate(180/NumSides)
	cylinder(d=FrictionDisk[LENGTH]/cos(180/NumSides),h=ArmLength/2,$fn=NumSides);
	translate([ArmLength – FrictionDisk[LENGTH]/2,0,0])
	sphere(d=FrictionDisk[LENGTH],$fn=NumSides);
	}
	}
	rotate(180/6) {
	PolyCyl(FrictionDisk[ID],FrictionDisk[LENGTH] + 2*Protrusion,6,Center=true);
	for (k=[-1,1])
	translate([0,0,k*(FrictionDisk[LENGTH]/2 – Divots[LENGTH]/2)])
	PolyCyl(Divots[OD],Divots[LENGTH] + Protrusion,6,Center=true);
	}
	}
	}

	// Basic hot shoe socket

	module ShoeSocket() {

	difference() {
	union() {
	cube(ShoeBlock,center=true); // overall blocky retainer
	translate([-ShoeBlock.x/2,0,0])
	cylinder(d=ShoeBlock.x,h=ShoeBlock.z,$fn=NumSides,center=true);
	}
	translate([0,0,-2*ShoeBlock.z]) // screw hole throughout
	rotate(180/6)
	PolyCyl(ShoeStem[ID],4*ShoeBlock.z,6);
	translate([0,0,ShoeBase.z/2]) // base slot under pillar
	cube([ShoeBase.x,ShoeBase.y,ShoeBase.z],center=true);
	translate([ShoeBase.x/2,0,ShoeBase.z/2]) // base slot opening
	cube([ShoeBase.x,ShoeBase.y,ShoeBase.z],center=true);
	translate([ShoeStem[OD]/2,0,ShoeBase.z/2 + ShoeStem[LENGTH]]) // stem slot
	cube([2ShoeStem[OD],ShoeStem[OD],2ShoeStem[LENGTH]],center=true);

	}
	}

	// Stick parts together

	module Mount() {
	rotate([90,0,0])
	LampArm();
	translate([ArmLength + ShoeBlock.x/2 – Protrusion,0,0])
	ShoeSocket();
	}

	//—–
	// Build things

	if (Layout == "Build") {
	rotate([0,90,0])
	translate([-(ArmLength + ShoeBlock.x),0,0])
	Mount();
	}

	if (Layout == "Show")
	if (Part == "LampArm")
	LampArm();
	else if (Part == "ShoeSocket")
	ShoeSocket();
	else if (Part == "Mount")
	Mount();

view raw Photo Light Bracket for Desk Lamp Arm.scad hosted with ❤ by GitHub

The original dimension doodles, made before I removed the stem and discovered the recesses around the screw hole:

Photo Light - Desk Lamp Arm Dimensions — Photo Light – Desk Lamp Arm Dimensions

2019-04-02

Vacuum Tube Lights: Triode

With the wrecked 5U4GB safely in the trash, I popped a smaller, somewhat less stately triode from the Big Box o’ Hollow-State Electronics and wired it up with a pair of SK6812 RGBW LEDs:

Triode - Purple-green phase — Triode – Purple-green phase

The tube’s markings have long since vanished, but, at this late date, all that matters is an intact glass envelope!

After two years, the ordinary white foam tape holding the knockoff Arduino Nano lost most of its sticktivity and easily popped off the 3D printed base:

Triode - Nano PCB - white strips — Triode – Nano PCB – white strips

Two layers of 3M outdoor-rated foam tape clear the bottom-side components and, based on current evidence, its stickiness should stick forever more:

Triode - Nano PCB - 3M strips — Triode – Nano PCB – 3M strips

The alert reader will notice the mis-soldered 1 kΩ SMT resistor above-and-right of the CH340 USB interface chip. I think those two resistors are the isolators between the 328P microcontroller and the CH340, letting you use the TX and RX lines as ordinary I/O without killing either chip.

Despite the mis-soldering, it evidently passed their QC and works fine. Seeing as how I didn’t notice it until just now, it’ll remain in place until I must open the lamp base for some other reason, which may never happen.

The data output is now on pin A5, to match the rest of the glowing widgetry:

Triode - Nano installed — Triode – Nano installed

Blobs of hot melt glue affix the SK6812 and wiring to the socket:

Triode - socket wiring — Triode – socket wiring

The original “plate cap” wiring ran directly through a hole in the hard drive platter, which I embiggened for a 3.5 mm panel-mount headphone jack. The knurled metal plug looms next to this smaller tube, but it looks better (in a techie sense) than the raw hole:

Triode - plate cap plug — Triode – plate cap plug

Octal tubes have an opaque Bakelite base, so I devoted some Quality Shop Time™ to the post:

Triode - base tip exposed — Triode – base tip exposed

Although I’d made a shell drill for 5U4’s base, this base was so crumbly I simply joysticked the spinning cutter around to knock off the rest of the post:

Triode - finished base — Triode – finished base

The shell drill would open the bottom to admit a bit more light. I may do that to see if it makes any visible difference.

I didn’t expect the serrations in the top mica plate to cast interesting patterns around the platter:

Triode - cyan-purple phase — Triode – cyan-purple phase

Memo to Self: use the shell drill to avoid nicking the evacuation tip!

2019-03-28

3D Printed Chain Mail Armor: Failure Analysis

While dropping some recent 3D printed odds-n-ends into the show-n-tell box, I discovered the large sheet of square chain mail armor had a missing link:

Chain Mail Armor - the missing link — Chain Mail Armor – the missing link

Fortunately, the link fell off in the box and I recovered all the pieces for a failure analysis:

Chain Mail Armor - failed link - glue spots — Chain Mail Armor – failed link – glue spots

I’d glued the PLA together with IPS #4, a hellish mixture of plastic solvents including methylene chloride, one of the few chemicals able to chew into PLA, but there’s not much penetration or bonding going on.

Let’s try that again with a bit more solvent.

First, slide the bars into place:

Chain Mail Armor - failed link - bars in place — Chain Mail Armor – failed link – bars in place

I applied four solvent drops in two passes to give it time to work its way in, put four matching drops on the armor cap, squished the cap in place, tweaked the bar alignment, then applied pressure while contemplating the whichness of the why for half a minute while the solvent worked its magic.

Things look pretty good once more:

Chain Mail Armor - missing link - repaired — Chain Mail Armor – missing link – repaired

There’s no way to determine the repair’s goodness, other than by deliberately trying to snap off a bar, so I’ll just put it back in the box and hope for the best.

2019-03-27

Injured Arm Support Table: Wide Version

This table must sit across the threshold of a walk-in / sit-down shower, with the shower curtain draped across the table to keep the water inside.

Starting with another patio side table, as before, I installed a quartet of 5 mm stainless screws to lock the top panels in place and convert the table into a rigid assembly:

Arm Supports - wide table - overview — Arm Supports – wide table – overview

Because the shower floor is slightly higher than the bathroom floor, I conjured a set of foot pads to raise the outside legs:

Patio Side Table Feet - OpenSCAD model — Patio Side Table Feet – OpenSCAD model

The sloping top surface on the pads compensates for the angle on the end of the table legs:

Arm Supports - leg end angle — Arm Supports – leg end angle

I think the leg mold produces legs for several different tables, with the end angle being Close Enough™ for most purposes. Most likely, it’d wear flat in a matter of days on an actual patio.

Using good 3M outdoor-rated foam tape should eliminate the need for fiddly screw holes and more hardware:

Arm Supports - leg pads — Arm Supports – leg pads

The feet fit reasonably well:

Arm Supports - leg pad in place — Arm Supports – leg pad in place

They may need nonskid tape on those flat bottoms, but that’s in the nature of fine tuning.

And, as with the narrow table, it may need foam blocks to raise the top surface to arm level. Perhaps a pair of Yoga Blocks will come in handy for large adjustments.

The OpenSCAD source code as a GitHub Gist:

	// Patio Side Table Feet
	// Ed Nisley – KE4ZNU
	// 2019-03

	/* [Layout Options] */

	Layout = "Build"; // [Show,Build]

	/* [Extrusion Parameters] */

	ThreadWidth = 0.40;
	ThreadThick = 0.25;

	HoleWindage = 0.2;

	Protrusion = 0.1;

	//—–
	// Dimensions

	TapeThick = 1.0; // 3M double-stick outdoor tape

	LegWall = [2.5,3.5]; // leg walls are not the same in X and Y!

	LegBase = [36.0,19.0]; // flat on floor
	LegOuter = [31.0,19.0]; // perpendicular to leg axis
	LegInner = [28.5,11.5]; // … ditto
	LegAngle = 90 – 53; // vertical to leg

	LegRecess = [LegInner.x,LegInner.y,LegInner.x*tan(LegAngle)];

	PadWedge = 2; // to fit end of leg
	PadRadius = 4.0; // rounding radius for nice corners
	PadBase = [LegBase.x + 2PadRadius,LegBase.y + 2PadRadius,5.0];
	PadSides = 6*4;

	BathStep = 20; // offset between shower bottom and floor


	/* [Hidden] */

	EmbossDepth = 1*ThreadThick; // recess depth

	DebossHeight = 1*ThreadThick + Protrusion; // text height + Protrusion into part

	//—–
	// Useful routines

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes

	Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

	FixDia = Dia / cos(180/Sides);

	cylinder(r=(FixDia + HoleWindage)/2,
	h=Height,
	$fn=Sides);
	}


	//—–
	// Foot pad

	module FootPad(Riser = 0.0) {

	difference() {
	union() {
	hull()
	for (i=[-1,1], j=[-1,1]) {
	translate([i(PadBase.x/2 – PadRadius),j(PadBase.y/2 – PadRadius),0])
	cylinder(r=PadRadius,h=1,$fn=PadSides);
	translate([i*(PadBase.x/2 – PadRadius),
	j*(PadBase.y/2 – PadRadius),
	Riser + PadBase.z – PadRadius – (i-1)*PadWedge/2])
	sphere(r=PadRadius/cos(180/PadSides),$fn=PadSides);
	}
	translate([PadRadius – PadBase.x/2,0,Riser + PadBase.z])
	rotate([0,LegAngle,0])
	translate([LegRecess.x/2,0,(LegRecess.z – Protrusion)/2 ])
	cube(LegRecess – [2TapeThick,0,2TapeThick],center=true);
	}
	translate([0,0,-2*PadBase.z]) // remove anything under Z=0
	cube(4*PadBase,center=true);

	cube([17,12,2*DebossHeight],center=true);
	}

	mirror([1,0,0])
	linear_extrude(height=EmbossDepth)
	translate([0,0,0])
	text(text=str(Riser),size=10,spacing=1.05,
	font="Arial:style=Bold",
	valign="center",halign="center");
	}


	//—–
	// Build things

	if (Layout == "Build") {
	if (true) {
	translate([-0.7PadBase.x,-0.7PadBase.y,0])
	FootPad(0);
	translate([-0.7PadBase.x,+0.7PadBase.y,0])
	FootPad(0);
	}
	translate([+0.7PadBase.x,-0.7PadBase.y,0])
	FootPad(BathStep);
	translate([+0.7PadBase.x,+0.7PadBase.y,0])
	FootPad(BathStep);
	}

	if (Layout == "Show")
	FootPad();

view raw Patio Side Table Feet.scad hosted with ❤ by GitHub

2019-03-26

Category: Machine Shop

Sony NP-FM50 Battery Disassembly

Broken Spoke

Seam Ripper Cover

Desk Lamp Conversion: Photo Light Cold Shoe

Vacuum Tube Lights: Triode

3D Printed Chain Mail Armor: Failure Analysis

Injured Arm Support Table: Wide Version