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.
After about five and a half years, the OEM shift indicator in my rear SRAM Grip Shift failed, so I replaced it with a piece of right-angle polypropylene backed with hot pink vinyl:
All done by hand, because it’s easy.
I’d used up my stock of genuine replacement indicators long ago, but they’re now down to two bucks (probably because Grip Shifters are obsolete) and I’ve stocked up in anticipation of future need.
Let’s see how long this one lasts …
While cutting some oak plywood, I managed to get some interesting (to me, anyhow) pictures of how the assist air interacts with the laser kerf:
The air flow is about 12 l/min from the pump in the bottom of the laser cabinet and is pushing most of the fumes through the kerf, where they ignite and burn merrily.
The plywood is up on magnetic punk spikes to give the fumes plenty of room to disperse without making too much of a mess on the bottom surface. Unfortunately, the flame can blowtorch the cut parts after they fall through onto the honeycomb.
Another view shows some smoke doesn’t make it through the kerf:
The bulk of the flame seems to trail behind the beam as it cuts through the wood, which isn’t surprising:
Just like acrylic flame, it’s kinda pretty, but should serve as another reminder why you must never, ever run your laser unattended.
Opening the garage door to start a morning of errands revealed a garter snake previously tucked neatly into the space below the door seal:
It’s somewhat smaller than the garter snake under the trash can, although I’m sure they’re closely related.
It was a cool morning and the snake hadn’t yet reached operating temperature, but it eventually flowed off into the garage and we went on our way.
A few hours later we returned:
Apparently that was the best place for a snake.
Mary lined up a four-cell seedling pot ahead of the critter, encouraged it to flow forward, and much to our surprise it tucked neatly into one of the cells:
We carried it to the herb garden, wished it well, and a few hours later it had uncoiled and gone about its business.
Unlike the Shoe Frog, it hasn’t been seen since.
While pondering what to do with the shattered kitchen scale, I got a bottom-dollar replacement touting its rechargeable lithium battery. After giving it the obligatory charge-before-using, I put it in service. Five days later, its battery was dead flat discharged.
So I gutted it to extract the battery:
It’s a cute little thing, isn’t it?
Much to my surprise, the obligatory battery rundown test showed it matches its 0.74 W·hr label:
We all know where this is going, right?
Crunche a connector on the battery, another on the scale, and make up a suitable current tap for a meter:
Which looked like this:
That’s about what I found for the craptastic scale running from a pair of CR2032 primary cells, so it’s not out of line.
Turn off the scale and measure the idle current:
Do you think I got a dud?
For all I know, the little microcontroller under the epoxy blob is running a continuous attack on my WiFi network, with the intent of siphoning off all my sensitive bits. Ya never know.
Dividing the battery’s 200 mA·hr rating by 4 mA says it really should be dead in 50 hours, which is close enough to five days: diagnosis confirmed!
Rather than fight, I switched to a battery with more capacity:
It’s long past its prime, but ought to last for a month, which is about as long as the shattered scale survived on a similar battery.
Sheesh & similar remarks.
What else would you call things that raise the back of a Moonlander keyboard:
The Moonlander comes with two adjustable struts, one for each keyboard half, which should hold the things at whatever angle you like. I put wood blocks underneath for better support, but finally gave up and laid out a quartet of elevators on scrap 3 mm acrylic:
The upper hole is 30 mm from the base and that’s the only one I needed, so they’re even easier to make than they look.
Done!
A backlash test found on the LightBurn forum puts the machine through a series of difficult maneuvers:
That’s burned on the back of a paperboard box at 400 mm/s @ 15%/10% power, which is slightly too intense for the smaller patterns.
The key point is that the machine has no detectable trace of backlash, with all the opposing lines matching up and equal spacing regardless of the approach direction.
Whew!
The acceleration may be a little too high, as seen on some recent beam alignment targets:
The larger targets on the right let the machine reach a speed closer to the nominal 400 mm/s around the arc, so the cut along the tape tab after the right-angle turn comes out a bit wobbly; the smaller targets are fine. The red lines are just under 0.5 mm wide and the wobble is on the same order, so it’s pretty close to being OK.
After deporting the same tree frog from her shoe five times over the course of a month, Mary finally admitted defeat:
We think this is the same frog who insisted on sunning itself on the railing back in June:
If that isn’t a smug smile, I don’t know what one might look like.
When she related this tale at a Master Gardener meeting, one of her cronies said a similar frog commandeered a shoe and refused all offers of a new home, so apparently tree frogs and shoes just go together.
Anybody that persistent deserves whatever it wants; Mary will get a new pair of shoes and keep them indoors.
The Smell of Molten Projects in the Morning 