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.
Attempting to use the guest WiFi network requires agreeing to their Terms of Use:
While it may be possible to read that, I pretty much gave up.
While one should never ascribe to malice what can be explained by stupidity, it’s also true that any sufficiently advanced stupidity is indistinguishable from malice.
Our medical practice has been Borged by Optum, which is, through a number of corporate cutout layers, owned by UnitedHealth Group, so (despite claims to the contrary) our doctors effectively work for a health insurance company. No, they may not be paid by UHG, but following the money in reverse shows the flow of influence.
Apparently this has slightly affected the original practice’s reliance on Phreesia for pre-visit sign-in information collection although, as before, Phreesia still really wants to scatter your precious personal bits to the far corners of the InterWebs:
The wall o’ text is a bit shorter then the earlier version and cannot be scrolled or printed. It still admits:
There is the potential for my health information … to be subject to redisclosure and to no longer be protected by the HIPAA Privacy Rule.
Yes, I understand that’s the whole point of getting me to agree to release my private bits to Phreesia, so they can make money by selling it to the highest bidder(s).
What’s new is the previous page in the sequence, of which I do not have a screenshot, presumably coming from Optum, emphasizing in bold type that I do not have to authorize Phreesia’s data collection.
I infer this means two things:
Yes, I understand that I have no privacy and should get over it, but somehow this sort of behavior rankles …
While setting up to drill holes in the aluminum base for the running light buck converter, I wondered if laser-marking the spots directly from the solid model would work better than my usual fumbling around.
The solid model:
Export projections of the pieces from OpenSCAD as an SVG file:
Import into LightBurn, set up for a very fast, very light cut and Fire The Laser:
That’s in ordinary masking tape on a hard-anodized sheet of aluminum from the pile, which looked better than I expected.
The same aluminum covered with blue tape:
Which looks much better in person than it does in the photo.
On a soft aluminum sheet from the Basement Warehouse Zone:
The dark outline is a comfort mark hand-drawn around a chipboard test piece to verify the layout fit between random holes drilled in the sheet during its previous life.
A closer look at a corner hole:
And the center hole:
The holes appeared in the right places after center-punching by eye, but the fragility of those four little tape leaves around the center point must be experienced to be believed.
And, yes, those are deliberately low-polygon approximations to a circle, because I’m a low-poly kind of guy.
I really need an optical center punch if I do more such silliness. The box with those HP plotter digitizing sights recently came to hand, so I suppose I should make something.
A pack of Black Laser Engraving Testing Paper arrived and I put a few snippets to the test:
That’s the standard backlash test pattern shrunken down to a little over an inch wide, with the laser power reduced to the bare minimum. Despite that, the numerous holes show where the pattern concentrates enough energy to vaporize the paper.
The “paper” seems to be laminated between two black plastic sheets that smell terrible when engraved, so they’re probably some form of acrylic. The Amazon product description is, despite all the verbiage- remarkably uncommunicative of the actual materials involved.
The circular pattern is 10 mm diameter on the outside:
Those should be circles around the perimeter, but their distortion shows what happens when you try to move a hulking CO₂ laser head around a 1.5 mm diameter circle at 400 mm/s. Of course, the actual speed is nowhere near that fast along such tiny vectors.
The traces are about 0.2 mm wide, with obvious scorches where the beam starts and stops, which agrees reasonably well with previous measurements.
All in all, both the paper and the laser pattern look better than I expected, particularly as the results indicate the machine has no measurable backlash at all.
A new battery for my electrified Tour Easy recumbent arrived. It has newer 21700 lithium cells in the same overall box, but the baseplate requires new blocks adapting it to the frame:
The top profile fits snugly into the battery mounting plate, with clearance on the sides for the latches:
However, I had enough trouble measuring those recesses that I broke down and added a projection() view to the OpenSCAD code:
Exporting that as an SVG image and importing it into LightBurn let me cut it out of chipboard:
Obviously, it took several iterations to fit the top profile to the baseplate, particularly after finding slightly different measurements at each block position. On the other paw, laser cutting the profiles proceeded much more quickly than 3D printing just a few millimeters of the block, so it was a net win.
The new battery baseplate doesn’t have an internal space for the buck converter feeding the running lights, so there’s more construction ahead.
One of the folding wood chairs that Came With The House™ had a loose arm that turned out to be due to a missing chunk of wood:
The obvious lay of the grain shows why it failed like that, surely hastened by the crack below the screw.
So I cut a snippet of brass tubing that, mirabile dictu, fit both the hole and the M6 screw, mixed up some wood epoxy and buttered it up:
The crack extended entirely through the arm and was more extensive that seemed reasonable to expect the epoxy to handle on its own:
So I slobbered soaked saturated the cracks with wood hardener and clamped them shut:
The hardener is intended to solidify rotted wood, but it makes a reasonable adhesive and, being much more liquid than ordinary wood glues, seemed like it would penetrate further into the cracks than anything else on hand. We shall see how this works out.
Rummaging in the Drawer o’ M6 Screws produced a better match to the brass tube than the original flat head screw:
It screws into a fancy tee nut in the upright chair rail, where a dot of thread locker should hold it forevermore.
I hit the exposed end with some sandpaper to smooth off the last of those smears and, after a few years, it’ll probably look like it grew there.
It seems all the drain boards under dish drainers are now intended for contemporary under-counter sinks without a rim, which is not the Old School drop-in sink we have in the kitchen. After considerable faffing about, I hacked a fix to make the drain board & drainer fit the sink:
The crude notch not only lowers the front edge by a few millimeters, it also encourages the lip to stay over the sink, rather than sliding back over the counter and slobbering water everywhere.
The drain board has stiffening ribs under the center section, cleverly arranged so they do not actually touch the counter. I measured the shape of the board near the ribs:
And then cut shapes to both support the board and rest on the counter:
The board has a swale in the middle, directly over those ribs, requiring more tilt for proper drainage:
Getting all of that flying in formation required several iterations and we’re still not entirely satisfied, but at least the water flows into the sink and does not puddle in the drain board or on the counter.
Stipulated: wood is the wrong material for the job, hot melt glue is breathtakingly ugly, and you want no part of this.
You can buy fancier drain boards, some with cute spouts leading into the sink, but the fine print suggests most expect to work with rimless under-counter sinks.
The Smell of Molten Projects in the Morning 