Machine Shop – Page 212 – The Smell of Molten Projects in the Morning

MicroMark Bandsaw: Blackened Table

The really bright LED worklights I added to the MicroMark bandsaw produced plenty of glare from the raw aluminum table top:

USB Gooseneck Mount - on bandsaw — USB Gooseneck Mount – on bandsaw

No good deed goes unpunished, I suppose.

While rooting around for something else, I rediscovered my bottle of Birchwood Casey Aluminum Black (basically selenium dioxide) that’s intended for touchup work on small parts, not blackening an entire aluminum plate. Well, having had that bottle forever, it’s not like I’ll miss a few milliliters.

If this didn’t work, I could always sand the table down to the original aluminum finish.

So I applied a sanding block in hopes of smoothing the tooling marks:

MicroMark Bandsaw - sanded table — MicroMark Bandsaw – sanded table

Looked pretty good, I thought, so:

Wipe it down with alcohol (per the bottle instructions)
Slather on a generous dose of Aluminum Black
Let that chew on the table for a minute
Rinse off with water, wipe dry
Perch atop the furnace for thorough drying
Spray with Topsaver oil, wipe down
Put it back on the bandsaw

Aaaaand it looks great:

MicroMark Bandsaw - blackened table — MicroMark Bandsaw – blackened table

Well, in terms of metal finishing, that blackening job looks downright crappy. Aluminium Black is intended for decorative work and will surely wear quickly on the bandsaw table, but it’s entirely good enough for my simple needs: the glare from those lights is gone.

After I took the picture, I blackened the brass screw in the slot. Came out a weird mottled green-bronze, might look antique in a different context, suits me just fine.

Done!

2017-02-10

Kenmore Progressive Vacuum Cleaner Carpet Brush Disassembly

The beater bar found and ingested a remarkably long strip of carpet yarn, resulting in a sudden stop and an acute need for disassembly. In the unlikely event that happens again:

Remove hose
Release latch to lay hose fitting flat
Remove two obvious screws
Pry rear latches adjacent to hose fitting to release rear of top cover
Pry side latches to release middle of top cover
Pull rear of top cover away from base
Disengage latches along front of beater bar

Those places, neatly marked for future reference, with the top cover against the floor:

Kenmore Progressive vacuum - carpet brush - disassembly latches — Kenmore Progressive vacuum – carpet brush – disassembly latches

With the cover off, the beater bar lifts out and you can easily unwind the mess.

2017-02-09

Forester: TPMS FTW, Redux

Now I know the Forester’s TPMS icon blinks on 1000 feet from a cold start with 12 psi in the offending tire. I returned home and pulled this from a sipe in the left rear tire:

Road debris - blade fragment — Road debris – blade fragment

It’s atop a 0.1 inch grid.

The flat side on the right rode tangent to the tire surface, recessed slightly below the tread, and pretty much invisible inside the sipe. Of course, the point punched through the tire’s steel belt and let the wind out, ever so slowly.

I initially thought it was a utility knife blade fragment, but under the microscope it looks more like a saw blade tooth. It’s obviously been kicking around on the road for quite a while; back in the day, they occasionally swept the roads, but that was then and this is now.

Makes me glad I didn’t buy four new tires after the last flat. I suppose installing two plugs in the same tire counts as a net loss, but they’re small, widely separated injuries and that’s how it’ll roll.

For the record: with 14 k miles on the tires, tread wear = 2/32 inch of the original 6/32 inch depth.

Those tires should last another 30 k miles at our current pace, although I expect more random debris will kill one stone cold dead before that.

2017-02-08

Bandsaw Worklight: LED Cable Clips

Adapting the sewing machine cable clips for larger USB cables:

LED Cable Clips - solid model — LED Cable Clips – solid model

The calculation positioning the posts wasn’t quite right; they now touch the cable OD at their midline and converge slightly overhead to retain it.

They’re great candidates for sequential printing:

LED Cable Clips - Slic3r - sequential print — LED Cable Clips – Slic3r – sequential print

With the basement at 14 °C, any cooling is too much: the platform heater can’t keep the bed above the thermal cutout temperature, the firmware concludes the thermistor has failed, and shuts the printer off. So I popped the four finished clips off the platform, removed the skirt, unplugged the fan, rebooted that sucker, and restarted the print.

One clip in the front keeps the cable away from the power switch and speed control directly below the gooseneck mount:

USB Gooseneck Mount - cable clip — USB Gooseneck Mount – cable clip

A few clips in the back route the cable from the COB LED epoxied directly onto the bandsaw frame away from the motor enclosure:

Bandsaw platform COB LED - cable clips — Bandsaw platform COB LED – cable clips

They’re mounted on double-sided foam tape. The COB LED on the frame isn’t anything to write home about, but you can see the foam tape peeking out around the clip base:

Unlike those LED filaments, it seems you can gently bend the aluminum substrate under a COB LED.

The bandsaw platform now has plenty of light: a fine upgrade!

Yeah, you can buy stick-on cable anchors, but what’s the fun in that? These fit exactly, hold securely, and work just fine.

The OpenSCAD source code as a GitHub Gist:

	// LED Cable Clips
	// Ed Nisley – KE4ZNU – October 2014
	// February 2017 – adapted for USB cables

	Layout = "Show"; // Show Build

	//- Extrusion parameters must match reality!

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2; // extra clearance

	Protrusion = 0.1; // make holes end cleanly

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

	//———————-
	// Dimensions

	Base = [15.0,15.0,6*ThreadThick]; // base over sticky square

	CableOD = 3.8;

	BendRadius = 5.0;

	CornerRadius = Base[0]/5;
	CornerSides = 4*4;

	NumSides = 6*3;

	//– Oval clip with central passage

	module OvalPass() {

	intersection() {
	hull()
	for (i=[-1,1], j=[-1,1])
	translate([i(Base[0]/2 – CornerRadius),j(Base[1]/2 – CornerRadius),0])
	rotate(180/CornerSides)
	cylinder(r=CornerRadius,h=Base[2] + 1.00*CableOD,$fn=CornerSides,center=false);

	union() {
	translate([0,0,Base[2]/2]) // oversize mount base
	scale([2,2,1])
	cube(Base,center=true);

	for (j=[-1,1]) // bending ovals
	translate([0,j(Base[1]/2 – 0.125(Base[1] – CableOD)/2),(Base[2] – Protrusion)])
	resize([Base[0]/0.75,0,0])
	cylinder(d1=0.75*(Base[1]-CableOD),
	d2=(Base[1]-CableOD)/cos(0*180/NumSides),
	h=(CableOD + Protrusion),
	center=false,$fn=NumSides);
	}
	}

	if (Layout == "Show")
	color("Red",0.3)
	translate([0,0,Base[2] + CableOD/2])
	rotate([0,90,0])
	cylinder(d=CableOD,h=2*Base[0],center=true,$fn=48);

	}

	//———————-
	// Build it

	OvalPass();

view raw LED Cable Clips.scad hosted with ❤ by GitHub

2017-02-07

Bandsaw Worklight: USB Gooseneck Mount

The bandsaw now sports a chunky mount for its gooseneck light:

The gooseneck ends in a USB Type-A plug, so an ordinary USB extension cable can connect it to the hacked hub supplying 9 VDC:

USB Gooseneck Mount - interior — USB Gooseneck Mount – interior

The plastic came from a slightly earlier version of the solid model, with one foam pad under the gooseneck’s USB plug to soak up the clearance. The four smaller holes, with M3 brass inserts visible in the bottom half (on the right), clamp the gooseneck connector in place against the foam; you could push it out if you were really determined, but you’d have to be really determined.

If I ever build another one, it’ll sandwich the plug between opposing pads:

USB Gooseneck Connector Mount - Slic3r preview — USB Gooseneck Connector Mount – Slic3r preview

The lettering on the block stands out much better in the solid model:

USB Gooseneck Connector Mount - solid model - overview — USB Gooseneck Connector Mount – solid model – overview

Obviously, I need help with the stylin’ thing. This looks better, but with terrible overhangs for printing in the obvious no-support orientation:

USB Gooseneck Connector Mount - solid model - rounded top — USB Gooseneck Connector Mount – solid model – rounded top

Anyhow, the USB extension cable (on the left) has plenty of clearance and pulls straight out of the housing, so I can remove the bandsaw cover without unwiring:

USB Gooseneck Mount - assembled — USB Gooseneck Mount – assembled

The LED ticks along at 40 °C in a 14 °C basement, suggesting a thermal coefficient around 14 °C/W. Even in the summer months, with the basement around 25 °C, there’s no risk of PETG softening at 50 °C.

I’ll epoxy a similar 1.8 W COB LED onto the curve of the bandsaw frame where it can shine on the left and rear part of the table; it doesn’t even need a case.

The OpenSCAD source code as a GitHub Gist:

	// Gooseneck lamp for MicroMark bandsaw
	// Ed Nisley KE4ZNU
	// February 2017

	Layout = "Mount"; // Mount Show Build

	Gap = 5; // distance between halves for Show

	//- Extrusion parameters must match reality!

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

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

	//———————-
	// Dimensions

	Tap10_32 = 0.159 * inch;
	Clear10_32 = 0.190 * inch;
	Head10_32 = 0.373 * inch;
	Head10_32Thick = 0.110 * inch;
	Nut10_32Dia = 0.433 * inch;
	Nut10_32Thick = 0.130 * inch;
	Washer10_32OD = 0.381 * inch;
	Washer10_32ID = 0.204 * inch;

	ID = 0; // for round things
	OD = 1;
	LENGTH = 2;

	Insert = [3.0,4.9,2*ThreadThick + IntegerMultiple(4.2,ThreadThick)]; // M3 short brass insert

	CornerRadius = 5.0; // rounded mount block corners for pretty
	CornerSides = 4*4;

	RoundedTop = true; // true for fancy smooth top edges

	USBPlug = [39.0,16.0,8.3]; // plug, X from base of plug
	USBSocket = [28.0,20.0,11.5]; // USB extension, X from tip of socket

	USBMating = [-12.0,0,0]; // offset of plug base relative to block center

	Foam = [35.0,10.0,2.0 – 1.0]; // foam pad to secure USB plug (Z = thickness – compression)

	GooseneckOD = 5.0; // flexy gooseneck diameter

	MountScrewOC = 35.0; // make simple screw hole spacing for bandsaw case

	MountBlock = [10*round((USBPlug[0] + USBSocket[0] + 5.0)/10),
	10*round((MountScrewOC + Washer10_32OD + 5.0)/10),
	// 26ThreadThick + IntegerMultiple(max(USBPlug[2],USBSocket[2]),ThreadThick)];
	16.0]; // thickness = 16 mm M3x0.5 button head screw

	echo(str("Block size: ",MountBlock));

	LegendDepth = 2*ThreadThick; // lettering depth

	//———————-
	// Useful routines

	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);
	}

	//– Mount

	module Mount() {

	difference() {
	hull()
	if (RoundedTop) {
	for (i=[-1,1], j=[-1,1])
	translate([i(MountBlock[0]/2 – CornerRadius),j(MountBlock[1]/2 – CornerRadius),0]) {
	translate([0,0,-MountBlock[2]/2])
	rotate(180/CornerSides)
	cylinder(r=CornerRadius,h=MountBlock[2]/2,$fn=CornerSides,center=false);
	translate([0,0,MountBlock[2]/2 – CornerRadius])
	rotate(180/CornerSides)
	sphere(r=CornerRadius,$fn=CornerSides,center=true);
	}
	}
	else {
	for (i=[-1,1], j=[-1,1])
	translate([i(MountBlock[0]/2 – CornerRadius),j(MountBlock[1]/2 – CornerRadius),0])
	rotate(180/CornerSides)
	cylinder(r=CornerRadius,h=MountBlock[2],$fn=CornerSides,center=true);
	}
	for (j=[-1,1]) // screws into bandsaw case
	translate([0,j*MountScrewOC/2,-(MountBlock[2]/2 + Protrusion)])
	rotate(180/8)
	PolyCyl(Clear10_32,(MountBlock[2] + 2*Protrusion),8);
	for (i=[-1,1], j=[-1,1]) { // clamp screws
	translate([iMountBlock[0]/4,jMountScrewOC/2,-MountBlock[2]])
	PolyCyl(Insert[ID],2*MountBlock[2],6); // clearance
	translate([iMountBlock[0]/4,jMountScrewOC/2,-(MountBlock[2]/2 + Protrusion)])
	PolyCyl(Insert[OD],Insert[LENGTH] + Protrusion,6); // inserts
	}
	rotate([0,90,0]) // gooseneck flexy cable
	rotate(180/6)
	PolyCyl(GooseneckOD,MountBlock[0],6);

	translate([USBPlug[0]/2,0,0] + USBMating – [Protrusion/2,0,0]) // USB plug outline
	cube(USBPlug + [Protrusion,0,0],center=true);
	translate([-USBSocket[0]/2,0,0] + USBMating) // USB socket outline
	cube(USBSocket,center=true);

	translate([(Foam[0]/2 + 5*ThreadWidth),0,-(Foam[2]/2 + USBPlug[2]/2)] + USBMating – [Protrusion,0,-Protrusion]/2) // foam padding recess
	cube(Foam + [Protrusion,0,Protrusion],center=true); // foam packing
	translate([(Foam[0]/2 + 5*ThreadWidth),0, (Foam[2]/2 + USBPlug[2]/2)] + USBMating – [Protrusion,0, Protrusion]/2) // foam padding recess
	cube(Foam + [Protrusion,0,Protrusion],center=true);

	render(convexity=5)
	translate([0,0,MountBlock[2]/2 – LegendDepth])
	linear_extrude(height=LegendDepth + Protrusion) {
	translate([0,5,0])
	text(text="KE4ZNU",size=8,spacing=1.10,font="Bitstream Vera Sans:style=Bold",valign="center",halign="center");
	translate([0,-5,0])
	text(text="4 Feb 2017",size=6,spacing=1.05,font="Bitstream Vera Sans:style=Bold",valign="center",halign="center");
	}
	}
	}

	//———————-
	// Build it

	if (Layout == "Mount") {
	Mount();
	}

	if (Layout == "Show") {
	translate([0,0,-Gap/2])
	difference() {
	Mount();
	translate([0,0,MountBlock[2]])
	cube(2*MountBlock,center=true);
	}
	translate([0,0,Gap/2])
	difference() {
	Mount();
	translate([0,0,-MountBlock[2]])
	cube(2*MountBlock,center=true);
	}
	}

	if (Layout == "Build") {
	translate([0,0.6*MountBlock[1],MountBlock[2]/2])
	difference() {
	Mount();
	translate([0,0,MountBlock[2]])
	cube(2*MountBlock,center=true);
	}
	translate([0,-0.6*MountBlock[1],MountBlock[2]/2])
	rotate([180,0,0])
	difference() {
	Mount();
	translate([0,0,-MountBlock[2]])
	cube(2*MountBlock,center=true);
	}
	}

view raw USB Gooseneck Connector Mount.scad hosted with ❤ by GitHub

2017-02-06

Proto Board Holders: 80×120 mm

Another stack of proto boards arrived, this time 80×120 mm, and I ran off another pair of holders:

Proto Board Holder - 80x120 - tooling — Proto Board Holder – 80×120 – tooling

Not wanting to, ahem, screw around with the lathe, the screws got themselves shortened the old-fashioned way: by hand, with the screw cutter, then filed and passed through a 4-40 die to clean up the threads.

Bah!

2017-02-05

Bandsaw Worklight

Having hacked back the end of the USB gooseneck extension, a tweak of the COB LED heatsink mount for my desk lamp produces a smaller version for a 1.8 W LED:

Chip On Board Heatsink Mount - Bandsaw Lamp - solid model — Chip On Board Heatsink Mount – Bandsaw Lamp – solid model

That fits half of a random heatsink, bandsawed just to the far side of the middle fin and milled flat.

Ream out the 5 mm hole with a #8 drill for a snug fit around the gooseneck, jam gooseneck in place, dab epoxy on the corners of the recess, mash the heatsink in place, solder wires to LED, smear epoxy on the aluminum backplate, clamp while curing:

USB Gooseneck - LED assembly — USB Gooseneck – LED assembly

And it looks pretty good, if I do say so myself:

USB Gooseneck - on bandsaw — USB Gooseneck – on bandsaw

The hook-n-loop tape holding the cable to the bandsaw gotta go, but should suffice until I conjure a better mount.

The alert reader may wonder how a 9 V COB LED runs from a 5 V USB cable with nary a trace of a voltage booster to be seen. Well, that’s not really a USB cable any more; I paralleled the red+white and black+green wires for lower resistance, then hacked a 9 VDC power supply into an old USB hub:

Hacked USB hub - PCB mods — Hacked USB hub – PCB mods

I ripped out the upstream USB plug, hotwired the 9 V supply where the 5 V USB wires used to be, soldered jumpers on the downstream sockets to short the outer two pin pairs together, razor-knifed the power leads going into the epoxy-blobbed USB controller, and declared victory:

Hacked USB hub - in use — Hacked USB hub – in use

Admittedly, that “In Use” LED runs a bit brighter now.

I have a few other tools on that bench in need of LED lights; when I build ’em, they can all plug into this hub. No reason to invent new connectors & cables & all that. It may need a power switch.

Turns your stomach, eh?

The OpenSCAD source code as a GitHub Gist:

	// Chip-on-board LED light heatsink mount for desk lamp
	// Ed Nisley KE4ZNU December 2015
	// February 2017 – rectangular COB, smaller heatsink

	Layout = "Show"; // Show Build

	//- Extrusion parameters must match reality!

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

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

	//———————-
	// Dimensions

	ID = 0; // for round things
	OD = 1;
	LENGTH = 2;

	Gooseneck = [3.0,5.0,15.0]; // anchor for end of gooseneck

	COB = [30.0,11.0,2.5]; // Chip-on-board LED module

	Heatsink = [37.1,19.2,10.0]; // overall
	HeatsinkBase = 2.0; // solid base below fins

	HSLip = 1.0; // width of lip under heatsink

	BaseMargin = 22ThreadWidth;
	BaseRadius = 3*ThreadThick + Gooseneck[OD]/2; // defines slab thickness
	BaseSides = 2*4;

	Base = [(Gooseneck[LENGTH] + Gooseneck[OD] + Heatsink[0] + 2*BaseRadius + BaseMargin),
	(Heatsink[1] + 2BaseRadius + 2BaseMargin),
	2*BaseRadius];

	echo(str("Slab thickness: ",Base[2]));

	//———————-
	// Useful routines

	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);
	}

	//– Lamp heatsink mount

	module Lamp() {

	difference() {
	translate([(Base[0]/2 – BaseRadius – Gooseneck[LENGTH]),0,0])
	hull()
	for (i=[-1,1], j=[-1,1])
	translate([i(Base[0]/2 – BaseRadius),j(Base[1]/2 – BaseRadius),Base[2]/2])
	sphere(r=BaseRadius/cos(180/BaseSides),$fn=BaseSides);

	translate([(Heatsink[0]/2 + Gooseneck[OD]), // main heatsink recess
	0,
	(Base[2] + Heatsink[2]/2 – HeatsinkBase)])
	cube((Heatsink + [HoleWindage,HoleWindage,0.0]),center=true);

	translate([(Heatsink[0]/2 + Gooseneck[OD]),0,HeatsinkBase]) // lower lip to shade lamp module
	scale([1,1,2])
	cube(Heatsink – [2HSLip,2HSLip,0],center=true);

	translate([0,0,Base[2]/2]) // goooseneck insertion
	rotate([0,-90,0]) rotate(180/8)
	PolyCyl(Gooseneck[OD],Base[0],8);

	translate([0,0,Base[2]/2 + Gooseneck[ID]/2]) // wire exit
	rotate([180,0,0])
	PolyCyl(Gooseneck[ID],Base[2],6);

	translate([Gooseneck[OD],0,(Base[2] – HeatsinkBase – Protrusion)/2]) // wire slot
	rotate([180,0,0])
	cube([2*Gooseneck[OD],Gooseneck[ID],(Base[2] – HeatsinkBase + Protrusion)],center=true);

	}

	}

	//———————-
	// Build it

	if (Layout == "Show") {
	Lamp();
	}

	if (Layout == "Build") {

	}

view raw Chip On Board Heatsink Mount.scad hosted with ❤ by GitHub

2017-02-04

Category: Machine Shop

MicroMark Bandsaw: Blackened Table

Kenmore Progressive Vacuum Cleaner Carpet Brush Disassembly

Forester: TPMS FTW, Redux

Bandsaw Worklight: LED Cable Clips

Bandsaw Worklight: USB Gooseneck Mount

Proto Board Holders: 80×120 mm

Bandsaw Worklight