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.

Author: Ed

Simpleminded Photographic Light Box

The general idea of a light box is (wait for it) a uniform background in a box full of bright light:

Light Box – overview

Obviously, this is a low-budget light box, but it makes perfect sense if you already have an essentially unlimited supply of moving boxes, 11×17 inch plotter paper, and a couple of photo / video lights lying around.

A two-layer cardboard ring glued to the top keeps the light from sliding off the box and stiffens the gaping hole letting the light shine through.

You’d normally use a fabric background to get rid of those ugly gaps around the edges and a larger box would be better, so this is along the lines of a proof-of-concept.

From the camera’s viewpoint, it looks better than my crusty desktop cutting mat:

Light Box – gears overview

Those gears would not look out of place in Bowman’s bedroom in 2001: A Space Odyssey.

In this day and age, you’d normally use a phone camera:

Light Box – gears overview – DOF

The lens on my Pixel 6a has a fixed focal length (around 4.4 mm = 27 mm equivalent) and a fixed f/1.8 (-ish) aperture, producing a razor-thin depth of field at the rear of the front gears. Note the fuzzy gears in the background, all of three inches away, and the slightly fuzzy front edge of the front gears. The camera’s digital zoom doesn’t help matters in the least, despite the AI-powered interpolation.

Keeping things close together helps, although the far end of the wipe towers and the rear of the gears lose detail:

Light Box – gears stacked

Looking from above also helps a little, but a top viewing port would reduce the skewed perspective:

Light Box – gears detail – DOF

Shallow DOF keeps your attention on the foreground, which is why real photographers use it for portraits:

Light Box – gears standing – DOF

The camera, an ancient Sony DSC-H5 with a zoom lens going down to f/8, still does nice work through a 2× macro adapter lens:

Light Box – gear detail – top light

The DOF is still narrow, but at least the entire front gear is in focus.

Adding a front light picks out the knurling:

Light Box – gears detail – front light

The results definitely look better than before, but it’ll take a bit of getting used to traipsing to the Basement Laboratory for every photo …

2024-09-23
Husky Workbench Caster Feet

The flat robot vacuum assigned to clean the floors around here would occasionally get stuck under the leg of my Husky workbench-as-desk and fail to complete its mission. Living in the future makes solving that problem a matter of minutes:

Husky workbench caster feet – installed

The upper rim captures the locked-in-place wheel in a 35×25 mm recess atop the middle 45×35 mm slab, with a 2.5 mm cork layer on the bottom. Laser-cut, of course, glued with ordinary yellow wood glue, and clamped for about half of a Squidwrench remote meeting.

Raising the desk by 5.5 mm gives the Flat One juuust enough clearance to scuttle under there:

Husky workbench caster feet – vacuum clearance

That was easy …

2024-09-20
Pill Desiccant

One of my Old Guy medicines has an elaborate desiccant container:

Pill desiccant container

Being that type of Old Guy, I weighed the container when I emptied the bottle, then left it sit in the kitchen cabinet with the scale for a week as the weight slowly increased.

It started at 2.38 g and stabilized at 2.56 g, so it absorbed 0.18 g of water from the air after it got my attention.

Peeling the label revealed an obvious joint:

Pill desiccant – contents

Looks like HO-scale coal in there!

The desiccant weighs all of 1.20 g, so it absorbed something more than 10% of its weight. That’s less than I found with silica gel, but I don’t know the starting weight or how much moisture it already absorbed.

A newly opened pill bottle disgorged a container weighing 2.42 g. The initial weight obviously depends on many variables, none of which would be tightly controlled.

2024-09-19
Royal Carting Truck: Squeeze Play

I’m riding downhill from Red Oaks Mill toward the bridge across the Wappinger Creek, pedaling a bit over 24 mph = 37 feet/sec, far enough into the lane to avoid trash along the curb on the right:

Royal front 2024-09-13 – 078

Although you can barely see the vehicle passing on my left, I’ve just realized I am in one heap of trouble.

Half a second later (the frame number in the caption ticks along at 60 fps) I’m caught in the slipstream:

Royal front 2024-09-13 – 108

Another half second and I’m leaning slightly to the right:

Royal front 2024-09-13 – 138

Make that wobbling:

Royal front 2024-09-13 – 158

Well, that’s a relief:

Royal front 2024-09-13 – 178

The truck is now completely within our lane and I’m further to the right, so our paths really were converging:

Royal front 2024-09-13 – 208

Elapsed time: 2.2 seconds.

The view from the rear shows the driver started with reasonable clearance (these frames tick at 30 fps):

Royal rear 2024-09-13 – 090

A second later, the dumpster grabber is about even with my handlebars, corresponding to the first helmet camera picture:

Royal rear 2024-09-13 – 120

A third of a second later:

Royal rear 2024-09-13 – 130

The rear wheels passed much closer:

Royal rear 2024-09-13 – 180

In general, Royal’s drivers give us plenty of clearance.

In this case, I think he badly misjudged how fast I was moving and figured he would be well past by the time he had to be completely in the right lane to avoid vehicles in the left-turn lane on the bridge.

However, intent wouldn’t make me any less dead after a trip around those tires …

2024-09-18
Miniature Planetary Gear Bearings

Because it’s easy to scale solid models:

Small Planetary Gear Bearings – PETG PETG-CF

The small bearings are 25 mm OD, with correspondingly small clearances between their moving parts, but they all spun easily after a bit of breaking in.

As with their larger cousins, the orange PETG bearing has the most axial play and worked just fine right off the platform. The gray PETG-CF bearing was jammed and required concerted effort to get the gears rolling, but now has essentially no axial play while turning easily. The snappy-looking orange and black bearing has very little play and feels the best of the three.

The single-material bearings take about 20 minutes to print, while the mixed material one requires 80 minutes due to the extruder purging and nozzle clearing. The larger mixed material bearing took more than three hours, but time doesn’t scale as the cube of the size because changing materials runs at a constant time:

Small Planetary Gear Bearings – PETG PETG-CF with wipe towers

The smaller mixed gear produced the smaller wipe tower on the right, but changing materials remains an expensive process. Of course, if you were doing this in production, you’d make a couple dozen of the little things in one job: the machine would spend most of its time squirting out planetary gear bearings with the same number of material changes building the same size wipe tower.

They’re slightly too small for my fingers and surely pose a choking hazard to children, but they’re definitely cute.

2024-09-17
Revised Measuring Spoon Drainer

A small tweak to the venerable spoon drainer adds a configurable cutout adapting it to a slightly different dish drainer rack:

Measuring Spoon Drainer – solid model

Which lets it snuggle into the corner:

Measuring spoon drainer – installed

Both the old and new racks had coated steel loops stuck into rubberoid feet perfectly suited to collect water and eventually rust the loops. Given a new rack, I figured potting the feet in JB PlasticBonder urethane adhesive would help forestall the rust:

Rubbermaid dish drainer – foot potting

I wish it were white, rather than black, but the only other color choice is tan and I can’t wish nearly that hard.

Along those lines, however, the gray JB Weld epoxy coating on the cheese slicer and the smaller repairs on the big knife are doing fine after years of use. JB Weld is good stuff!

2024-09-16
Planetary Gear Bearing Fondletoy: M2 vs MK4

It’s been about a decade since I made a batch of planetary gear fondletoys:

Planetary Gear Bearing – black red natural

So I loaded up the same STL in Prusaslicer and made three more:

Planetary Gear Bearing – M2 vs MK4

Both pictures show the same red bearing, done in PLA on the Makergear M2. The other bearings are PETG and PETG-CF on the Prusa MK4 + MMU3.

The blue bearing has about 5 mm of axial play, a bit more than the red.

The gray bearing is PETG-CF and has maybe 1 mm of axial play, which agrees with my original observation that an Extrusion Multiplier of 1.0 results in slightly overstuffed carbon fiber parts. It’s not much and, frankly, produces a better fit in this case, but it’s different than pure PETG. Which should come as no surprise, of course, given that it’s 15% carbon.

The gray-and-orange bearing looks spectacular in person and has about 3 mm of axial play, roughly the same as the red bearing, which you’d expect from overstuffed PETG-CF and pure PETG.

The single-color bearings print in about 1.5 hours and the two-color one weighed in over four hours. Multi-material objects are do-able, but you gotta want the results.

I told Prusaslicer to wipe the orange filament into the gray infill during color changes (per the Wipe Tower doc), but those two gray parts have so little infill as to make no difference:

Planetary Gear Bearing – PETG PETG-CF with wipe tower

The wipe tower in that posed photo has a nubbly texture because the filament just gets squirted without regard to anything other than maintaining the basic tower shape.

Seeing things appear on the platform never gets old!

2024-09-13