The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: Machine Shop

Mechanical widgetry

Hiatus

After devoting the last few months to setting up the Makerspace Starter Kit and extracting / organizing / stashing the stuff I wanted to keep:

New parts cabinets

I now have some difficulty accomplishing what needs to be done:

Basement Shop – right

During the rest of May I must write a pair of columns, unpack / arrange / reinstall my remaining tools / parts / toys, endure a road trip to our Larval Engineer’s graduation (*), enjoy bicycling with my Lady, and surely repair a few odds-n-ends along the way.

I’ll generate occasional posts through June, after which things should be returning to what passes for normal around here…

(*) For reasons not relevant here, our Larval Engineer’s schedule includes a final co-op and wind-up semester after “graduation”. Perhaps she’s entering the Chrysalis phase of her development?

2016-05-06
Makerspace Starter Kit: Shipped!

So I spent the last month (*) extracting the tools, parts, and stock I use on a regular basis, filling 20-ish boxes with stuff I wanted to keep:

Basement shop – right – before

After I moved all those boxes out of the way, three very industrious guys (and two teens who gradually got into the spirit of the thing) from MakerSmiths devoted all of a Saturday and a bit of Sunday morning converting an entire basement like that into this:

Basement Shop – right

The stuff filled about 3/4 of the floor space in a pair of 26 foot box trucks:

Each truck had a snug 10,000 pound load limit and the stuff didn’t stack well:

The strap under the pile of metal, plus some plywood stiffeners, prevented it from running amok during transit. As long as they didn’t flip the truck, everything seemed well packed and cross-braced.

Only a few minor injuries; all’s well that ends well.

Alas, most of the spatial memory that let me find a tool or a part is now wrong; it’ll take a while to re-learn the new locations.

(*) Samuel Johnson: “… when a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully.”

2016-04-30
Macrophotography Exposure Calculator

Back in high school, I designed and built a slide rule exposure calculator to improve my macro photographs:

Macrophotography Exposure Calculator – front

The base consists of three layers of thin cardboard glued together with Elmer’s Glue. The three slides have three layers of thinner white cardboard glued together, with offsets forming tongue-and-groove interlocks, topped with yellow paper for that true slide rule look:

Macrophotography Exposure Calculator – slide detail

Judging from the seams, I covered the hand-drawn scales with “invisible” matte-surface Scotch Tape. Worked well, if you ask me, and still looks pretty good:

Macrophotography Exposure Calculator – front – detail

The reverse side carries instructions under a layer of packing tape (which hasn’t survived the test of time nearly as well), for anyone needing help:

Macrophotography Exposure Calculator – rear

A closer look at the instructions:

Macrophotography Exposure Calculator – instructions

The slides still move, albeit stiffly, and it might be usable.

I vaguely recall extension tubes on an early SLR, but memory fades after that. Getting the exposure settings close to the right value evidently posed something of a challenge and, given the cost of 35 mm film + development, it made sense to be careful.

Fortunately, even today’s low-end cameras make macro photography, at least for my simple needs, easy enough, with the camera handling the exposure calculations all by itself:

SX230HS – macro lens – 15 x 20 mA ring light

I’m definitely not on the level of a professional insect photographer!

Randy’s observation to Amy in Neal Stephenson’s Cryptonomicon comes to mind:

“… One of the most frightening things about your true nerd, for many people, is not that he’s socially inept — everybody’s been there — but rather his complete lack of embarrassment about it.”

“Which is kind of pathetic.”

“It was pathetic when they were in high school,” Randy says. “Now it’s something else. Something very different from pathetic.”

“What, then?”

“I don’t know. There is no word for it. You’ll see.”

2016-04-27
OttLite LED Conversion: Lamp Shell Auto-Disassembly

The converted OttLite hit the floor again and, this time, the shell around the lamp popped free. Given that I didn’t know how to take it apart before, this is new news.

There’s a small snap latch inside the bottom / inner surface:

OttLite LED Conversion – lamp shell – ventral

And two guide notches + latch nubs inside the top / outer surface:

OttLite LED Conversion – lamp shell – dorsal

So, if you had to get it apart by hand, a spudger-like tool applied to the bottom / inside of the shell and a bit of tugging should do the trick.

It snapped back together without incident, but I really must figure out a bigger base for the damn thing.

2016-04-26
Brother PT-1090 Tape Cartridge Innards

Mad Phil gave me his Brother PT-1090 labeler, which I’ve been using rather often of late. The white tape cartridge (the TZ flavor) ran out, giving me the opportunity to pry it apart:

Brother P-Touch TZ tape cartridge – disassembled

Surprisingly, a few small pins molded into the cover, plus a few obvious latches, hold it together without a trace of glue or thermal welding.

A detail of the little factory that assembles the label from several parts:

Brother P-Touch TZ tape cartridge – detail

Colored paper tape unwinds from the lower right and the top plastic layer from the lower left. Tape with thermal dye unspools from the upper left, the printhead (in the printer) heat-transfers pixels to the plastic tape in the opening right of center along the top, and the roller at the top right joins the just-printed plastic layer to the slightly sticky front surface of the paper tape. The used imaging tape respools in the gray cylinder near the middle.

For those concerned with privacy, that gray spool of used imaging tape contains everything you’ve printed in order:

Brother P-Touch TZ tape cartridge – imaging tape

I thought the thermal dye was part of the transparent tape cover layer, but in retrospect that doesn’t make sense: the printed tape would turn black in hot environments like, say, your car. So the printer must transfer the dye from a separate tape.

The knockoff “ESD” tape cartridges from Amazon seem to have a slightly different tape path, probably to work around Brother’s patents. I’ll pry one of those apart in due course.

2016-04-25

Clover Seam Ripper Cap

Mary wanted a rigid cap for a Clover seam ripper that came with a small plastic sheath, so I called one from the vasty digital deep:

Clover Seam Ripper - new cap — Clover Seam Ripper – new cap

The solid model looks about like you’d expect, with a brim around the bottom to paste it on the platform:

Clover Seam Ripper Cap - Slic3r preview — Clover Seam Ripper Cap – Slic3r preview

I added a slightly tapered entry to work around the usual tolerance problems:

Clover Seam Ripper Cap - bottom view — Clover Seam Ripper Cap – bottom view

The taper comes from a hull wrapped around eight small spheres:

Clover Seam Ripper Cap - Entry Pyramid — Clover Seam Ripper Cap – Entry Pyramid

That’s surprisingly easy to accomplish, at least after you get used to this sort of thing:

hull() {																		// entry taper
	for (i=[-1,1] , j=[-1,1])
		translate([i*(HandleEntry[0]/2 - StemRadius),j*(HandleEntry[1]/2 - StemRadius),0])
			sphere(r=StemRadius,$fn=4*4);
	for (i=[-1,1] , j=[-1,1])
		translate([i*(HandleStem[0]/2 - StemRadius),j*(HandleStem[1]/2 - StemRadius),HandleEntry[2] - StemRadius])
			sphere(r=StemRadius,$fn=4*4);	
}

The side walls are two threads thick and, at least in PETG, entirely too rigid to slide on easily. I think a single-thread wall with a narrow ridge would provide more spring; if this one gets too annoying, I’ll try that.

The OpenSCAD source code as a GitHub gist:

	// Clover seam ripper cap
	// Ed Nisley KE4ZNU – April 2016

	//- Extrusion parameters – must match reality!
	// Build with a 5 mm brim to keep it glued to the platform

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	Protrusion = 0.1;

	//——
	// Dimensions

	StemRadius = 0.50; // corner radius

	HandleStem = [6.1, 7.1, 9.0];

	HandleEntry = HandleStem + [1.0,1.0,-4.0]; // Z is -(straight part of stem)

	Cap = [8.5,11.0,45.0]; // XY exterior, Z interior


	//———————-
	//- Build it

	difference() {
	union() {
	translate([0,0,Cap[2]/2]) // main body column
	cube(Cap,center=true);

	translate([-Cap[0]/2,0,Cap[2]]) // rounded cap
	rotate([0,90,0])
	cylinder(d=Cap[1],h=Cap[0],$fn=8*4);

	translate([Cap[0]/2 – Protrusion,0,(Cap[2] + Cap[1]/2)/2]) // text
	rotate([0,90,0])
	linear_extrude(height=ThreadWidth,convexity=10)
	text("Mary Nisley",halign="center",valign="center",size=0.5*Cap[1],font="Arial");
	}

	hull() // stem + blade clearance
	for (i=[-1,1] , j=[-1,1])
	translate([i(HandleStem[0]/2 – StemRadius),j(HandleStem[1]/2 – StemRadius),-Protrusion])
	cylinder(r=StemRadius,h=Cap[2] + Protrusion,$fn=4*4);

	hull() { // entry taper
	for (i=[-1,1] , j=[-1,1])
	translate([i(HandleEntry[0]/2 – StemRadius),j(HandleEntry[1]/2 – StemRadius),0])
	sphere(r=StemRadius,$fn=4*4);
	for (i=[-1,1] , j=[-1,1])
	translate([i(HandleStem[0]/2 – StemRadius),j(HandleStem[1]/2 – StemRadius),HandleEntry[2] – StemRadius])
	sphere(r=StemRadius,$fn=4*4);

	}
	}

view raw Clover Seam Ripper Cap.scad hosted with ❤ by GitHub

2016-04-22

Belt Pack Zipper Pull Re-Repair

In our last episode, the zipper tab on my belt pack had worn through:

Eroded YKK Zipper Tab

I “fixed” that by the simple expedient of running a key ring through the latch that used to hold the tab. That held for half a year, which isn’t to be sniffed at for a zero-cost repair.

A few days ago, the abused latch popped off the slider, leaving the NSA tag and ring in my hand:

Belt Pack Zipper – missing tab and latch

I scuffed up the surface with a file to provide a bit more grip for the inevitable epoxy, then clamped a brass tube athwart the slider:

Belt Pack Zipper – wired brass tube

The tube ID passes the ring with enough clearance to make it work out. The general idea is that the tube provides rigidity for the ring, the wires hold the tube against the pull, and the epoxy holds the wires in place. I fully expect the sharp edges around the tube’s ID will gradually wear away.

Threading 14 mil stainless steel wire through the slider’s pivot hole:

Belt Pack Zipper – wire opened end

… and under the latch guide:

Belt Pack Zipper – wire closed end

… required a few tries and produced some nasty puncture wounds, but eventually it all hung together long enough to let me tuck some JB Kwik epoxy into all the nooks and crannies:

Belt Pack Zipper – epoxy curing

That’s wide masking tape covering the work area. As it turned out, good preparation like that meant I didn’t slobber epoxy anywhere it shouldn’t go; had I omitted the tape, there’d be a smear down the side of the pack.

Fast-forward to the next morning and it’s all good:

Belt Pack Zipper – repaired

The missing latch locked the slider in place, but I think I can eke out a miserable existence with a loose slider…

2016-04-21