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

Roof Rake

If they think you’re crude, go technical; if they think you’re technical, go crude. I’m a very technical boy. So I decided to get as crude as possible. These days, thought, you have to be pretty technical before you can even aspire to crudeness.
William Gibson — Johnny Mnemonic

Now that the trees have shed most of their leaves / needles, it’s time to get the accumulation off the roof edges. Fortunately, the upstairs windows overlook the biggest piles and, after I considered and rapidly rejected the notion of using the wind stick, Mary convinced me a roof rake would suffice by deploying a too-short broom.

After considering and rejecting several decreasingly elaborate variations of 3D-printed pole-to-pusher-plate adapter nonsense that almost involved our pole saw, this happened:

Roof Rake – in use

The wood pole comes from a left-behind assortment atop the garage’s open ceiling joists and the pusher plate comes from the cardboard box treasure trove.

A laser cutter makes close-fitting rings and hot-melt glue sticks those plates together with gleeful abandon:

Roof Rake – detail

The blue-and-white cardboard plate consists of two box flaps glued together, the glued-up stack of half a dozen rings transfers the torque from the plate to the pole, and the whole affair took the better part of fifteen minutes from idea to cool-enough glue.

It’s back on the garage joists for next year, unless we decide that pole has a higher purpose in life. Worst case, it loses two inches of length.

Bonus: Chore accomplished before the predicted weekend snowfall!

2024-11-21
Prusa MK4 Bling

While figuring out an X Axis homing problem (about which, more later), I printed a bunch of add-ons for the Prusa MK4, all from printables.com.

Stipulated: Using something other than black PETG and PETG-CF would make them more like bling.

The heatsink fan gets a scoop inlet to keep fingers and tools farther from the blades:

Prusa MK4 – fan cover – fan duct

The small upward duct on the right side directs the exhaust air away from the platform. This is apparently critical for very high-temperature plastics like ABS and PC, but I did have one print fail due to excessively cold breezes on the platform.

I made three different ducts in case I break one:

Prusa MK4 – fan ducts on platform

The aluminum extrusions now have dust covers:

Prusa MK4 – Extrusion cover – front

There’s also an angled heater cable connector cover, with a matching cover on the electronics box routing the cable rearward to dress it away from the hulking extruder cable:

Prusa MK4 – Extrusion cover – rear

And the Z axis stepper mounts have tidy dust covers:

Prusa MK4 – Z axis motor cover

None of which are necessary, but they’re all easy to print while thinking of other things.

2024-11-20
Sears Sewing Table: Caster Pads

Mary’s much-improved / -repaired Sears Sewing Table wanted to move around on the wood floor in the Sewing Room, so I captured its casters in little pads:

Sears Sewing Table caster pad – installed

A layer of 1 mm cork with PSA adhesive provides griptivity against the floor, a solid layer of 3 mm plywood spreads the wheel force over the cork, and a top ring of 3 mm plywood captures the wheel.

Which looked like this during gluing:

Sears Sewing Table caster pad – gluing fixtures

The scrap on the left served to align cork & plywood; it came from the plywood contributing the shapes. The ring around the cork is a glued-up pair of plywood rings (4 mm wide, outset from the perimeter of the pads) serving to align the two plywood layers.

Verily: time spent making a fixture is never wasted!

And having a laser cutter makes fixtures trivially easy, at least for simple fixtures like those.

2024-11-18
Layered Paper: Mariner’s Compass in Colors

Having recently shotgunned Amazon’s selection of colored art paper, this becomes possible:

Mariners Compass – inset browns

It’s the same geometry as the plain white layered version, with somewhat more attention to detail, and consists of a dozen layers glued and stacked on an assembly fixture.

The quilt-block version uses simple layering:

Layered Paper – Mariners Compass – Beyer 133

No commercial potential, but I like the effect.

2024-11-12

Wire Plant Stand Feet

A pair of plant stands from a friend’s collection ended up in Mary’s care and cried out for feet to keep their welded steel wire legs from scratching the floor:

Admittedly, it’s not the prettiest stand you can imagine, but the sentimental value outweighs all other considerations.

The feet are shrink-wrapped around the legs with enough curviness to look good:

Wire plant stand feet - show side view — Wire plant stand feet – show side view

With a drain hole in the bottom to prevent water from rusting the wires any more than they already are:

Wire plant stand feet - show bottom view — Wire plant stand feet – show bottom view

I briefly considered a flat bottom at the proper angle to sit on the floor, but came to my senses; it would never sit at the proper angle.

The end results snapped into place:

Wire plant stand feet - indoor detail — Wire plant stand feet – indoor detail

Of course the other stand, at first glance identical to the one above, has a different wire size and slightly different geometry, which I only discovered after printing another trio of feet. Changing the appropriate constants in the OpenSCAD program and waiting an hour produced a better outcome:

Wire plant stand feet - outdoor stand — Wire plant stand feet – outdoor stand

Living in the future is good, all things considered.

The OpenSCAD code as a GitHub Gist:

	// Wire plant stand feet
	// Ed Nisley KE4ZNU
	// 2024-11-06

	Layout = "Show"; // [Show,Build,Leg,LegPair,FootShell,Foot,Section]

	/* [Hidden] */

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

	TOP = 0;
	BOT = 1;

	FootLength = 30.0; // vertical foot length

	LegRings = // [255.0,350.0,300.0]; // top dia, bottom dia, vertical height
	[260.0,312.0,300.0];

	WireOD = //4.6 + 0.4; // oversize to handle bent legs
	5.7 + 1.0;

	DrainOD = 4.0; // drain hole in the bottom

	LegWidth = // [65.0,9.7]; // outer width at top & bottom
	[95.0, 12.0];

	LegAngle = atan((LegWidth[TOP] – LegWidth[BOT])/(2*LegRings[LENGTH]));

	StandAngle = atan((LegRings[TOP] – LegRings[BOT])/(2*LegRings[LENGTH]));

	WallThick = 3.0;

	FootWidth = 2*[WallThick,WallThick] +
	[LegWidth[BOT] + LegWidth[TOP]*FootLength/LegRings[LENGTH],LegWidth[BOT]];
	echo(FootWidth=FootWidth);

	NumSides = 234;

	Protrusion = 0.1;

	//—– Set up pieces

	module Leg() {

	hull()
	for (k = [0,1])
	translate([0,0,k*LegRings[LENGTH]])
	sphere(d=WireOD,$fn=NumSides);
	}

	module LegPair() {

	for (i = [-1,1])
	translate([i*(LegWidth[BOT] – WireOD)/2,0,0])
	rotate([0,i*LegAngle,0])
	rotate(180/NumSides)
	Leg();
	hull() // simulate weld for flat bottom
	for (i = [-1,1])
	translate([i*(LegWidth[BOT] – WireOD)/2,0,0])
	rotate([0,i*LegAngle,0])
	rotate(180/NumSides)
	sphere(d=WireOD,$fn=NumSides);
	}

	module FootShell() {

	difference() {
	hull() {
	for (i = [-1,1]) {
	translate([i*((FootWidth[BOT] – WireOD)/2 – WallThick),0,0])
	rotate(180/NumSides)
	sphere(d=(WireOD + 2*WallThick),$fn=NumSides);

	translate([i*((FootWidth[TOP] – WireOD)/2 – WallThick),0,FootLength – WireOD/2])
	rotate(180/NumSides)
	sphere(d=(WireOD + 2*WallThick),$fn=NumSides);
	}
	}
	translate([0,0,FootLength + FootLength/2])
	cube([2FootWidth[TOP],10WallThick,FootLength],center=true);
	rotate(180/NumSides)
	cylinder(d=DrainOD,h=4*FootLength,center=true,$fn=NumSides);
	}
	}

	module Foot() {

	difference() {

	FootShell();
	hull()
	LegPair();

	}

	}

	//—– Build it

	if (Layout == "Leg")
	Leg();

	if (Layout == "LegPair")
	LegPair();

	if (Layout == "FootShell")
	FootShell();

	if (Layout == "Foot")
	Foot();

	if (Layout == "Section")
	difference() {
	Foot();
	cube([FootWidth[TOP],(WireOD + 2WallThick),2FootLength],center=false);
	}

	if (Layout == "Show") {
	rotate([StandAngle,0,0]) {
	Foot();
	color("Green",0.5)
	LegPair();
	}
	}

	if (Layout == "Build")
	translate([0,0,FootLength])
	rotate([0*(90-StandAngle),180,0])
	Foot();

view raw Wire plant stand feet.scad hosted with ❤ by GitHub

2024-11-08

Curtain Rod Spring Pusher Block

Spotted during Autumn Window Cleaning:

Curtain rod pusher block – spring contortion

That’s the compression spring inside the curtain rod over the kitchen sink, intended to push the ends against the cabinets on either side. The screw slides along the outer rod and when tightened, backstops the spring against the inner rod.

The end of the spring is apparently intended to twist and jam inside the inner half of the rod, but that seemed so … unesthetic.

Being in the midst of setting up a Windows 11 box for the laser cutter, I used it as an excuse to fiddle with the RDP configuration to get LightBurn running in full screen mode on the monitor atop my desk; more about all that later.

The little pusher block is a hull around a pair of circles the same diameter as the smaller dimension of the inner rod, spaced apart enough to match its width, then laser-cut from a scrap of 1/4 inch acrylic:

Curtain rod pusher block – overview

Which assembles as you’d expect:

Curtain rod pusher block – installed

The spring seems much happier pushing against the block, doesn’t it?

Admittedly, this was completely unnecessary, but if you think of it as a side effect of the Win 11 thing, it makes at least a little sense.

2024-11-07
Sears Humidifier: Bottle Patching

Although the Sears humidifier (Model 758.154200 if you’re keeping score) that Came With The House™ works fine with its lid hinges broken, Mary heard an odd hissing sound somewhere inside. The sound continued with the thing unplugged and, after a protracted struggle in the kitchen sink, we tracked the sound to a crack in one of the dimples joining the front and back faces of the right-side water bottle:

Sears Humidifier bottle – overview

The vertical shaded bars come from the camera’s electronic shutter vs. unfiltered 60 Hz AC powering the shop LED lights.

Unsurprisingly, replacement bottles are no longer available, although you can get fill caps and valves, plus wicking filters.

A water drop squeezed in the crack:

Sears Humidifier bottle – crack

The bottles are polyethylene that sneers at any normal sealant, but I have a few square inches of tape intended for repairs exposed to weather. I didn’t get the snippet aligned just as I wanted, but its gooey adhesive definitely covered the crack:

Sears Humidifier bottle – patched

The bottles normally operate with a slight vacuum, thus the air hissing through the crack, so the tape need not withstand any continuous pressure and the adhesive layer should flow into the crack if it goes anywhere at all.

Protip: the gooey adhesive bonds instantly and irrevocably to whatever it touches, so do a trial fit before you peel off the backing tape.

If the “Serial” is a date code, it’s been around for while:

Sears Humidifier – data plate

It should be good for a few more decades …

2024-11-06