Category: Machine Shop

Mechanical widgetry

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
Laser Test Paper: Weathering

Three months of outdoor exposure suggest that laser test paper can survive use as a plant tag for one growing season, at least when it remains flat:

Laser test paper – small plant labels – 3 month exposure

The two upper tags demonstrated the paper has no flexibility worth mentioning, so it cannot become a tag wrapped around a stem.

The two lower labels spent their time tucked into a window frame where they got plenty of sun & rain without the benefit of a backing plate. Looks good to me!

Contrary to my expectation, the craft adhesive sheet behind this label survived intact, although the label itself took some damage, perhaps from the more direct sunlight out on the deck:

Laser test paper – plant marker – 3 month exposure

In any event, they look Good Enough™ for our simple needs and next year’s plants will be properly labeled.

2024-11-04
Leaf Engraving

A discussion about engraving leaves on the LightBurn forum prompted an experiment with a seasonally appropriate motif:

Engraved leaves

Those ran at 500 mm/s with 8 to 10% power, respectively the fastest speed & lowest power for my 60 W CO₂ laser.

The mmmm material has obvious irregularities and doesn’t lie flat:

Engraved leaf

A closer look:

Engraved leaf – detail

The line interval is an absurdly large 0.5 mm to keep the leaf from falling apart, as the laser burns almost completely through despite the low power.

I thought about scattering a bunch of these along the driveway, but came to my senses just in time …

2024-11-01