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.
Taking & making images.
This looks like a juvenile Cooper’s Hawk, perched high atop that tree. It seems the pair we spotted last year had a successful hatching!
We always wish “our” hawks, whatever and wherever they may be, good hunting…
This came from the first set of real pictures using the repaired Sony DSC-H5 zoomed to 12× with the 1.7× tele conversion lens, cropped down a bit: plenty of artifacts to choose from.
Having extracted the shutter button from the camera body, it’s easy to see why the plunger causes problems:
The plunger is basically a pin that eventually deforms the top of the switch membrane. Tee’s DSC-H1 had an exposed switch, although this picture shows that membrane was still in reasonably good condition:
My DSC-H5 has a thin black protective disk atop the switch, but the disk wasn’t particularly protective and developed a dimple that held the contacts closed even with the shutter button released (which is why I’m tearing the camera apart in the first place):
The C-clip around the plunger is now plastic, rather than metal, making it less likely to erode the thin plastic shaft. Pulling the clip off while holding the button down releases all the parts:
A few measurements from an intact shutter button, which may come in handy if you don’t have one:
Mount three-jaw chuck on the Sherline table, laser-align chuck to spindle, grab shutter button by its shaft in a Jacobs chuck, grab shutter button in three-jaw chuck, release from Jacobs chuck:
That’s not particularly precise, but it’s close enough for this purpose. I used manual jogging while testing the fit with a paper shim until all three jaws had the same clearance, then tightened the jaws.
I nicked the plunger at its base with a flush-cutting diagonal cutter, snapped off the plunger, and drilled a #56 hole through the button:
For reasons that made sense at the time, I repaired Tee’s DSC-H1 with a 1-72 brass screw. This time, I used an 0-80 (which I learned as ought-eighty, if you’re wondering about the indefinite article) screw and nut, because the screw head fit neatly into the bezel recess and I had a better idea of how to smooth out the threads.
This being plastic, I used the chuck to hold the tap in the proper alignment, then turned the tap through by finger pressure. This trial fit showed it worked:
Milling the nut down to a 2.8 mm cylinder required the usual manual CNC, with repeated iterations of this chunk of code in the MDI panel:
#<r>=[[2.8+3.11]/2] g1 x[-#<r>] f50 g0 z0 g2 i#<r> f100 g0 z4
The 2.8 in the first line is the current OD and the 3.11 is the measured diameter of the 1/8 inch end mill. I started from a 5.0 mm OD that just kissed the nut, then worked inward by 0.2 mm at a time for very shallow 0.1 mm cuts:
The alert reader will notice, as did I, that the head isn’t quite centered: the cut trimmed the left side and left the right untouched, with an offset far larger than the centering error. As nearly as I can tell, the heads of those screws aren’t exactly centered on their threaded shafts, but the final result fixed that… and the overall error is a few tenths of a millimeter = maybe 10 mils, tops, so it’s no big deal.
With all that in hand, I applied a very very thin layer of epoxy to fill the threads below the now-cylindrical nut and convert the screw into a rod:
My original intent was to use the screw head as-is atop the PET shield (per those instructions) on the switch membrane, but after reassembling enough of the camera to try that out, it didn’t work correctly: the half-pressed switch didn’t activate reliably before the full-pressed switch tripped.
The PET shield I used came from the side of a 1 liter soda bottle and turned out to be 0.27 mm thick:
I think the PET shield would work with the original plunger shape concentrating the force in the middle of the shield, but the nice flat screw head spreads the force out over a wider area. As a result, the force required to close the half-pressed switch contacts was roughly the same as that required to close the full-pressed contacts; remember the nub on the bottom of the black plastic tray concentrates the force in the middle of the full-pressed switch membrane.
So I removed the PET shield, added a dot of epoxy to fill the screw slot and compensate for the missing shield thickness, then filed a flat to make a nice pad:
Reassembling the camera once more showed it worked exactly the way it should. In fact, the button seems more stable than the OEM version, probably because the slightly enlarged plunger shaft fits better in the bezel. Too bad about those scuffs on that nice shiny button dome, though:
Tossing the leftover parts seems entirely appropriate…
The half-pressed shutter switch position on my Sony DSC-H5 recently stopped working, which seems to be one of two common failures. The other, a broken switch shaft, happened to Tee’s camera, as described there, and I figured I should preemptively fix that while I was inside my camera.
This being a common failure, several folks have described how to dismantle the camera; I followed that guide’s English version.
The DSC-H5 differs slightly from that description. After I got the thing apart, it became obvious that there’s no need to remove the LCD panel, the main control board, and most of the ribbon cables if you have a Philips #0 or #00 screwdriver with a very thin shaft. There’s no way to describe this operation, so take it apart his way, then you’ll see what I mean: the guts can come out as one big lump.
In any event, all the camera controls eventually emerge from the body:
Looking back into the camera body reveals the bottom of the shutter button, captured by a static discharge contact and the gray plastic frame of the Focus / Break button caps:
Removing the pushbutton frame and pushing the left button bezel latch with a small flat-blade screwdriver extracts the shutter button; it falls out of the inverted body. This is one of the few intact DSC-H[1-9] shutter buttons you’ll ever see:
Those rectangular protrusions lock into the slots in the black plastic cap that appears almost silver in this front view that shows the dimple in the switch membrane:
You must remove the cap to release the flex PCB with the shutter switches. Two heat-staked pins retain the cap; a scalpel neatly slices off the melted plastic:
Nota bene: the DSC-H1 button bezel I repaired earlier does not have features that lock into the cap over the switch assembly, which means you can remove and replace it without disassembling the camera. You cannot remove or install the DSC-H5 button without taking the camera apart. I suppose this counts as a continuous product improvement, but …
The shutter switch has two parts:
The bottom of the half-press tray has a small nub that activates the full-press switch, so the force required to activate the half-press switch must be considerably less than the force that activates the full-press switch. This turns out to be a critical part of the repair…
A closeup of the half-press switch with the protective cover sheet (the “damn confetti” of the disassembly instruction) and the dimple that held the contacts together with the button released:
A closeup of the switch through a snippet of PET plastic shows the switch membrane itself is in fine shape:
However, the new plastic shield did not work out well, for reasons having to do with the new button plunger. That’s the next step: rebuild the plunger…
We stopped at Lowell MA to visit the New England Quilt Museum (photography prohibited) and the Boott Cotton Mills Museum (photography encouraged). The NPS, among others, managed to salvage the buildings and restore some of the machinery, to the extent that one room on one floor of one building has some running cotton mills:
A bit more detail:
The original mills used water power, as did much of New England’s industry, but moments after Watt worked the bugs out of that newfangled steam engine, water power was history. The museum uses a huge old electric motor, mounted on the ceiling, to drive the line shafts above the mills; the vibration shakes the entire building and they hand out ear plugs at the door, despite having only half a dozen mills operating at any time. The working environment, horrific though it was, attracted employees (largely young women) from across the region; it was a better deal than they had on the family farm.
Employees were, of course, prohibited from using cotton to plug their ears…
They sell the cloth in the museum shop and we’ll eventually have some kitchen towels.
My father drew this in his Sophomore Biology Laboratory Notebook:
Can you imagine the attention span required to draw that with no obvious errors? The next four pages contain a hand-written discussion of the grasshopper, with two corrections; he filled the entire notebook using a pen and four colors of fluid ink.
Here’s a closer look at the grasshopper (clicky for more dots):
I cannot imagine assigning that task to present-day students…
Things were different in 1927, when he was 17 years old. They were about to get really different; 15 years later he was in the South Pacific.
That gas tank has evidently reached the end of its life:
Many of the nearby gas pipelines end in open stubs and a concrete crusher worked over one of the pads for a long-vanished cylindrical tank, so it looks like they’re scrapping the whole installation. I think the project to install an elevator for the Walkway lands nearby, which may explain everything.
I took the picture from the Walkway, aligning the SX230HS lens through the chain-link fence. Occasionally a small lens wins over more glass!
August was the month for giant orb weaving spiders; a pair of thumb-sized monsters took up residence under the gutter over the patio. One started by anchoring its web to the handrail by the steps:
While we like and encourage spiders, that anchorage didn’t last long and, yes, I must strip and repaint that railing…
There’s a horizontal web at the corner of the gutter over the back door:
Changing the exposure to favor the spider loses the web strands:
Cropping that one down around the spider shows they really are the stuff of nightmare:
The other spider prefers a vertical web attached along the gutter and anchored to a patio chair, which means I can get between the house and the web to see the spider’s tummy:
We leave the lights on in the evening for their benefit…
The Smell of Molten Projects in the Morning 